How to Understand Direct Indirect Speech

Direct and indirect speech

Introduction.
There two ways to convey a message of a person, or the words spoken by a person to other person.

1. Direct speech
2. Indirect speech

Suppose your friend whose name is John tells you in school, “I will give you a pen”. You come to home and you want to tell your brother what your friend told you. There are two ways to tell him.

Direct speech: John said, “I will give you a pen”.
Indirect Speech: John said that he would give me a pen.

In direct speech the original words of person are narrated (no change is made) and are enclosed in quotation mark. While in indirect speech some changes are made in original words of the person because these words have been uttered in past so the tense will change accordingly and pronoun may also be changed accordingly. In indirect speech the statement of the person is not enclosed in quotation marks, the word “that” may be used before the statement to show that it is indirect speech.  Indirect speech is also called reported speech because reported speech refers to the second part of indirect speech in which something has been told by a person.

Reporting verb: The verb first part of sentence (i.e. he said, she said, he says, they said, she says,) before the statement of a person in sentence is called reporting verb.

Examples. In all of the following example the reporting verb is “said”.
              He said, “I work in a factory”                           (Direct speech)
              He said that he worked in a factory.                (Indirect speech)
              They said, “we are going to cinema”               (Direct speech)
              They said that they were going to cinema.      (Indirect speech)

Reported Speech. The second part of indirect speech in which something has been told by a person (which is enclosed in quotation marks in direct speech) is called reported speech. For example, a sentence of indirect speech is, He said that he worked in a factory. In this sentence the second part “he worked in a factory” is called reported speech and that is why the indirect speech as a whole can also be called reported speech.

Fundamental rules for indirect speech.

1. Reported speech is not enclosed in quotation marks.
2. Use of word “that”: The word “that” is used as a conjunction between the reporting verb and reported speech.
3. Change in pronoun: The pronoun (subject) of the reported speech is changed according to the pronoun of reporting verb or object (person) of reporting verb (first part of sentence). Sometimes the pronoun may not change.

In following example the pronoun of reported speech is “I” which will be changed in indirect speech into the pronoun (Subject) of reporting verb that is “he”.

Example.
       Direct speech: He said, “I am happy”
       Indirect Speech: He said that he was happy.
       Direct speech: I said to him, “you are intelligent”
       Indirect Speech: I said him that he was intelligent. (“You” changed to “he” the                                                                                person of object of reporting verb)

1. Change in time: Time is changed according to certain rules like now to then, today to that day, tomorrow to next day and yesterday to previous day.

Examples.
Direct speech: He said, “I am happy today”
Indirect Speech: He said that he was happy that day.

1. Change in the tense of reported speech: If the first part of sentence (reporting verb part) belongs to past tense the tense of reported speech will change. If the first part of sentence (reporting verb part) belongs to present or future tense, the tense of reported speech will not change.

Examples.
   Direct speech: He said, “I am happy”
   Indirect Speech: He said that he was happy. (Tense of reported speech changed)
   Direct speech: He says, “I am happy”
   Indirect Speech: He said that he is happy. (Tense of reported speech didn’t                                                                                    change)

Table for change in tense of reported speech for all TENSES.

      TENSE CHANGE - IN - INDIRECT SPEECH
     Present simple tense into Past simple
     Present Continuous tense into Past continuous
     Present Perfect tense into Pas perfect
     Present Perfect Continuous into Past perfect continuous
     Past simple into Past Perfect
     Past Continuous into Past Perfect Continuous
     Past Perfect into Past Perfect
     Future simple, will into would
     Future Continuous, will be into would be
     Future Perfect, will have into would have

Examples.

DIRECT SPEECH	INDIRECT SPEECH
PRESENT TENSE
PRESENT SIMPLE changes into PAST SIMPLE
He said, “I write a letter” She said, “he goes to school daily” They said, “we love our country” He said, “he does not like computer”	He said that he wrote a letter. He said that she went to school daily. They said that they loved their country He said that he did not like computer.
PRESENT CONTINUOUS changes into PAST CONTINUOUS
He said, “he is listening to the music” She said, “I am washing my clothes” They said, “we are enjoying the weather” I said, “it is raining” She said, “I am not laughing”	He said that he was listening to the music. She said that she was washing her clothes. They said that they were not enjoying the weather. She said that she was not laughing.
PRESENT PERFECT changes into PAST PERFECT
She said, “he has finished his work” He said, “I have started a job” I said, “she have eaten the meal” They said, “we have not gone to New York.	She said that he had finished his work. He said that he had started a job. I said that she had eaten the meal. They said that they had not gone to New York.
PRESENT PERFECT CONTINUOUS changes into PAST PERFECT CONTINUOUS
He said, “I have been studying since 3 O’clock” She said, “It has been raining for three days.” I said, “She has been working in this office since 2007”	He said that he had been studying since 3 O’clock. She said that it been raining for three days. I said that she had been working in this office since 2007.
PAST TENSE
PAST SIMPLE changes into PAST PERFECT
He said to me, “you answered correctly” John said, “they went to cinema” He said, “I made a table” She said, “I didn’t buy a car”	He said to me that I had answered correctly. John said that they had gone to cinema. He said that he had made a table. She said that she had not bought a car.
PAST CONTINUOUS changes into PAST PERFECT CONTINUOUS
They said, “we were enjoying the weather” He said to me, “ I was waiting for you” I said, “It was raining” She said, “I was not laughing”	They said that they had been enjoying. He said to me that he had been waiting for me. I said that it had been raining. She said that she not been laughing.
PAST PERFECT changes into PAST PERFECT (tense does not change)
She said, “She had visited a doctor” He said, “I had started a business” I said, “she had eaten the meal” They said, “we had not gone to New York.	She said that she had visited a doctor. He said that he had started a business. I said that she had eaten the meal. They said they had not gone to New York.
FUTURE TENSE
FUTURE SIMPLE TENSE WILL changes into WOULD
He said, “I will study the book” She said, “I will buy a computer” They said to me, “we will send you gifts” I said, “I will not take the exam”	He said that he would study the book. She said that she would buy a computer. They said to me that they would send you gifts. I said that I would not take the exam.
FUTURE CONTINUOUS TENSE WILL BE changes into WOULD BE
I said to him, “ I will be waiting for him” She said,” I will be shifting to new home” He said, “I will be working hard” He said, “he will not be flying kite”	I said to him that I would be waiting for him. She said that she would be shifting to a new home. He said that he would be working hard. She said that he would not be flying kites.
FUTURE PERFECT TENSE WILL HAVE changes into WOULD HAVE
He said, “I will have finished the work” She said, “they will have passed the examination” He said, “I will have gone”	He said that he would have finished the work. She said that they would have passed the examination. He said that he would have gone.

Note: The tense of reported speech may not change if reported speech is a universal truth though its reporting verb belongs to past tense.

Examples.
       Direct speech: He said, “Mathematics is a science”
       Indirect Speech: He said that mathematics is a science.
       Direct speech: He said, “Sun rises in east”
       Indirect Speech: He said that sun rises in east. (Tense didn’t change because                                    reported speech is a universal truth thought its reporting verb                                    belongs to past tense)

 Indirect speech for Interrogative (question) sentence.

For changing interrogative (question) sentence into indirect speech we have to observe the nature of question and then change it into indirect speech according to it rules for indirect speech. A question can be of two types. One type which can be answered in only YES or NO and other type which needs a little bit explanation for its answer and cannot be answered in only YES or NO.

Examples
          Do you like music? (It can be answered in YES or NO)
          How are you? (It cannot be answered in YES or NO but it needs a little bit                                    explanation i.e, I am fine.)

Questions which can be answered in YES/NO.

To change questions (which can be answered in yes or no) into indirect speech, word “if” or “whether” is used before the question in indirect speech. Rules for change in tense of question sentences are same as for change in normal tenses in indirect speech but sentence will not start with the auxiliary verb of the tense. The word “that” is not used between reporting verb and reported speech as conjunction in indirect speech for question sentence. Question mark is not used in indirect speech.

Examples.
          Direct speech: He said to me, “do you like music?”
          Indirect Speech: He asked me if I liked music. (Not, did I like music)
          Or Indirect Speech: He asked me whether I liked music.
          
          Direct speech:  She said, “Will he participate in the quiz competition?”
          Indirect Speech: She asked me if he would participate in quiz competition.
          Direct speech: I said to him, “are you feeling well?”
          Indirect Speech: I asked him if he was feeling well.
          Direct speech: They said to me, “did u go to school?”
          Indirect Speech: They asked me if I had gone to school.
          Direct speech: He said to me, “Have you taken the breakfast?”
          Indirect Speech: He asked me if I had taken the breakfast

Question which cannot be answered in YES/NO.

To change such questions into indirect speech, the words “if” or “whether” is not used. The tense of the question is changed according to the rules for change in normal tenses in indirect speech but sentence will not start with the auxiliary verb of the tense. The word “that” is not used between reporting verb and reported speech as conjunction, in indirect speech for question sentence. Question mark is not used in indirect speech.

Examples.
             Direct speech: He said to me, “how are you?”
             Indirect speech: He asked me how I was. (Not, how was I)
             Direct speech: Teacher said to him, “what is your name?”
             Indirect speech: Teacher asked him what his name was.
             Direct speech: She said to him, “why did you come late?”
             Indirect speech: She asked him why he had come late.
             Direct speech: He said, “when will they come?”
             Indirect speech: He asked when they would come.
             Direct speech: She asked his son, “why are you crying?”
             Indirect speech: She asked her son why he was crying.

Indirect speech for sentence having MODALS, “can, may, must,

                               Present modals are changed to past modals

Direct Speech	Indirect Speech
Indirect speech for sentence having MODALS, “can, may, must, should, ought to”
CAN changes into COULD
He said, “I can drive a car” She said, “he can play a violin.” They said, “we can climb on a hill”	He said that he could drive a car. She said that he could play a violin. They said that they can climb on a hill.
MAY changes into MIGHT
He said, “I may buy a computer” She said, “he may visit a doctor.” They said, “they may go to zoo”	He said that he might buy a computer. She said that he might visit a doctor. They said that they might go to zoo.
MUST changes into HAD TO
He said, “I must work hard” She said, “they must carry on their work” I said to him, “you must learn the test-taking strategies”	He said that he had to work hard. She said that they had to carry on their work. I said to him that he had to learn the test-taking strategies.

 Indirect speech for sentence having MODALS, should, ought to, might, would, and could”

 

               The modal will not change in indirect speech

Direct Speech	Indirect Speech
THESE MODALS DO NOT CHANGE Would, could, might, should, ought to”
Would
They said, “we would apply for a visa” He said, “I would start a business. She said, “I would appear in exam”	They said that they would apply for visa. He said that he would start a business. She said that she would appear in the exam.
Could
She said, “she could play a piano” They said, “we couldn’t learn the lesson” He said, “I could run faster”	She said that she could play a violin. They said they couldn’t learn the lesson. He said that he could run faster.
Might
He said, “guests might come” She said, “it might rain” John said, “I might meet him”	He said that guest might come. She said that it might rain. John said that he might meet him.
Should
He said, “I should avail the opportunity” She said, “I should help a him” They said, “we should take the exam”	He said that he should avail the opportunity. She said that she should help him. They said that they should take the exam.
Ought to
He said to me, “you ought to wait for him” She said, “I ought to learn method of study” They said, we ought to attend our classes”	He said to me that I ought to wait for him. She said that she ought to learn method of study. They said that they ought to attend their classes.

Indirect speech for exclamatory and imperative sentences.

Indirect speech of imperative sentence.

A sentence which expresses command, request, advice or suggestion is called imperative sentence.
For example,
     •  Open the door.
     •  Please help me.
     •  Learn your lesson.

To change such sentences into indirect speech, the word “ordered” or “requested” or “advised” or “suggested” or “forbade” or “not to do” is added to reporting verb depending upon nature of imperative sentence in reported speech.

Examples.
           Direct speech: He said to me, “please help me”
           Indirect Speech: He requested me to help him.
           Direct speech: She said to him, “you should work hard for exam”
           Indirect Speech: He suggested him to work hard for exam.
           Direct speech: They said to him, “do not tell a lie”
           Indirect Speech: They said to him not to tell a lie.
           Direct speech: He said, “open the door”
           Indirect Speech: He ordered to open the door.
           Direct speech: The teacher said to student, “do not waste time”
           Indirect Speech: The teacher advised the students not to waste time.
           Direct speech: He said, “please give me glass of water”
           Indirect Speech: He requested to give him a glass of water.
           Direct speech: Doctor said to me, “Do not smoke”
           Indirect Speech: Doctor advised me not to smoke.
           Direct speech: The teacher said to him, “Get out”
           Indirect Speech: The teacher ordered him to get out.

Indirect speech of exclamatory sentences.

Sentence which expresses state of joy or sorrow or wonder is called exclamatory sentence.
For example.
             •  Hurrah! We won the match.
             •  Alas! I failed the test.
             •  Wow! What a nice shirt it is.

To change such sentences, the words “exclaimed with joy” or “exclaimed with sorrow” or “exclaimed with wonder” is added in the reporting verb depending upon the nature of exclamatory sentence in indirect speech.
Examples.
     Direct speech: He said, “Hurrah! I won a prize”
     Indirect Speech: He exclaimed with joy that he had won a prize.
     Direct speech: She said, “Alas! I failed in exam”
     Indirect Speech: She exclaimed with sorrow that she failed in the exam.
     Direct speech: John said, “Wow! What a nice shirt it is”
     Indirect Speech: John exclaimed with wonder that it was a nice shirt.
     Direct speech: She said, “Hurrah! I am selected for the job”
     Indirect Speech: She exclaimed with joy that she was selected for the job.
     Direct speech: He said, “Oh no! I missed the train”
     Indirect Speech: He exclaimed with sorrow that he had missed the train.
     Direct speech: They said, “Wow! What a pleasant weather it is”
     Indirect Speech:  They exclaimed with wonder that it was a pleasant weather.

Changes in pronoun in Indirect Speech.

 The pronoun (subject) of the reported speech is changed according to the
pronoun of reporting verb or object (person) of reporting verb (first part of sentence). Sometimes the pronoun may not change.

1. First person pronoun in reported speech i.e. I, we, me, us, mine, or our, is      changed according to the pronoun of reporting verb if pronoun in reporting verb      is third person pronoun i.e. he, she, it, they, him, his, her, them or their.
Examples.
         Direct speech: He said, “I live in New York”
         Indirect speech: He said that he lived in New York.
         Direct speech: They said, “we love our country”
         Indirect speech: They said that they loved their country

2. First person pronoun in reported speech i.e. I, we, me, us, mine, or our, is not     changed if the pronoun (Subject) of reporting is also first person pronoun i.e. I or     we.
Examples.
       Direct speech: I said, “I write a letter”
       Indirect speech: I said that I wrote a letter.
       Direct speech: We said, “we completed our work”
       Indirect speech: We said that we completed our work.

3. Second person pronoun in reported speech i.e. you, yours is changed according     to the person of object of reporting verb.
Examples.
        Direct speech: She said to him, “you are intelligent”
        Indirect speech: She said to him that he was intelligent.
        Direct speech: He said to me, “you are late for the party”
        Indirect speech: He said to me that I was late for the party.

4. Third person pronoun in reported speech i.e. he, she, it, they, him, his, her, them      or their, is not changed in indirect speech.
Examples.
    Direct speech: They said, “he will come”
    Indirect speech: They said that he would come.
    Direct speech: You said, “they are waiting for the bus”
    Indirect speech: You said that they were waiting for the bus.

Changes in time and adverbs in indirect speech.

Time and adverbs are changed in indirect speech.

Examples.
         Direct speech: He said, “I will buy a book tomorrow”
         Indirect speech: He said that he would buy a book the next day.
         Direct speech: She said, “I am happy now”
         Indirect speech: She said that she was happy then.
         Direct speech: He said, “I like this book”
         Indirect speech: He said that he liked that book.

Common Rules

Today changes to that day/the same day
Tomorrow changes to the next day/the following day
Yesterday changes to the day before/the previous day
Next week/month/year changes to the following week/month/year
Last week/month/year changes to the previous week/month/year
Now/just changes to then
Ago changes to before
Here changes to there
This changes to that

How to Understand Active and Passive Voice

Active and Passive Voice

There are two ways to express an action of a subject in relation to its object

• • Active voice
• • Passive voice

In “active voice” subject acts upon object, while in “passive voice” object is acted upon by subject. It can also be said, in “active voice” subject does a work on object, while in “passive voice” object is worked on by subject. The normal structure of an active voice sentence is subject+verb+object but in passive the normal structure of sentence is reversed according to certain rules and becomes like object+verb+subject. The real meaning of a sentence does not change if the sentence is expressed either by active voice or by passive voice. The active voice is mostly used in writing because it gives a direct and more concise meaning. Passive voice is used sometimes due to the following reasons.

1. When intentionally hiding the subject of sentence. For example, a student who failed in exam might say, some chapters were not studied.
   Another example. Women were not treated as equals
2. When passive voice better explain thought of sentence. For example, to say, cloth is sold in yards, is more meaningful than to say, Shop keepers sell cloth in yards.
3. When passive voice better emphasizes the main though of the sentence. For example, a man who is being teased by another person might say in anger, “you will be beaten by me”
4. When subject is not exactly known. For example, His watch was stolen. It is not known that who stole his watch, the subject (thief) is not exactly known so it is better to use passive voice for such sentence.There are certain rules for expressing a thought in passive voice or for changing a sentence from active voice to passive voice.

Fundamental Rules for changing from active voice to passive voice

1. The places of subject and object are interchanged i.e. the object shifts to the place of subject and subject shifts to the place of object in passive voice.

Example.
Active voice: I write a letter.
Passive voice: I letter is written by me.
Subject (I) of sentence shifted to the place of object (letter) and object (letter) shifted to the place of subject (I) in passive voice.

2. Sometimes subject of sentence is not used in passive voice. Subject of sentence can be omitted in passive voice, if without subject it can give enough meaning in passive voice.

Examples.
Passive voice: cloth is sold in yards

3. 3rd form of verb (past participle) is always used as main verb in sentences of passive voice for all tenses. Base form of verb or present participle will be never used in passive voice.
   The word “by” is used before subject in sentences in passive voice.

Example.
Active voice: He sings a song.
Passive voice: A song is sung by him.

4. The word “by” is not always used before subject in passive voice. Sometimes words “with, to, etc” may also be used before subject in passive voice.
   Examples.
   Active voice: The water fills the tub.
   Passive voice: The tub is filled with water.
   Active voice:  He knows me.
   Passive voice: I am known to him.
5. Auxiliary verbs are used passive voice according to the tense of sentence.

PASSIVE VOICE FOR ALL TENSES RULES

• The places of subject and object in sentence are inter-changed in passive voice.
• 3rd form of verb (past participle) will be used only (as main verb) in passive voice.
• Auxiliary verbs for each tense are given below in the table.

Present Simple Tense (passive Voice) Auxiliary verb in passive voice: am/is/are
Active voice: He sings a song. He does not sing a song.Does he sing a song?	Passive voice: A song is sung by him. A song is not sung by him. Is a song sung by him?

Present Continuous Tense (passive Voice) Auxiliary verb in passive voice: am being/is being/are being
Active voice: I am writing a letter I am not writing a letter. Am I writing a letter?	Passive voice: A letter is being written by me. A letter is not being written by me. Is a letter being written by me?

Present Perfect Tense (passive Voice) Auxiliary verb in passive voice: has been/have been
Active voice: She has finished his work She has not finished her work. Has she finished her work?	Passive voice: Her work has been finished by her. Her work has not been finished by her. Has her work been finished by her?

Past Simple Tense (passive Voice) Auxiliary verb in passive voice: was/were
Active voice: I killed a snake I did not kill a snake. Did I kill a snake?	Passive voice: A snake was killed by me. A snake was not killed by me. Was a snake killed by me?

Past Continuous Tense (Passive Voice) Auxiliary verb in passive voice: was being/were being
Active voice: He was driving a car. He was not driving a car. Was he driving a car?	Passive voice: A car was being driven by him. A car was not being driven by him. Was a car being driven by him?

Past Perfect Tense (Passive Voice) Auxiliary verb in passive voice: had been
Active voice: They had completed the assignment. They had not completed the assignment. Had they completed the assignment?	Passive voice: The assignment had been completed by them. The assignment had not been complete by them. Had the assignment been completed by them?

Future Simple Tense (Passive Voice) Auxiliary verb in passive voice: will be
Active voice: She will buy a car. She will not buy a car. Will she buy a car?	Passive voice: A car will be bought by her. A car will not be bought by her. Will a car be bought by her?

Future Perfect Tense (passive Voice) Auxiliary verb in passive voice: will have been
Active voice: You will have started the job. You will have not started the job. Will you have started the job?	Passive voice: The job will have been started by you. The job will not have been started by you. Will the job have been started by you?

Note: The following tenses cannot be changed into passive voice.

1. Present perfect continuous tense
2. Past perfect continuous tense
3. Future continuous tense
4. Future perfect continuous tense
5. Sentence having Intransitive verbs

Fundamental Rules

• The places of subject and object in sentence are inter-changed in passive voice.
• 3rd form of verb (past participle) will be used only (as main verb) in passive voice.
• Auxiliary verbs for each tense are given below in the table.

Passive voice for Present/Future Modals
“CAN, MAY, MIGHT, SHOULD, MUST, OUGHT TO”

• The places of subject and object in sentence are inter-changed in passive voice.
• 3rd form of verb (past participle) will be used only (as main verb) in passive voice.
• To change sentences having present/future modal into passive voice, auxiliary verb “be” is added after modal in sentence.

Passive voice for Present/Future Modals  “CAN, MAY, MIGHT, SHOULD, MUST, OUGHT TO” Auxiliary verb in passive voice: be
Active voice: CAN She can play a violin. She cannot play a violin. Can she play a violin?	Passive voice: CAN BE A violin can be played by her. A violin cannot be played by her. Can a violin be played by her?
Active voice: MAY I may buy the computer. I may not buy the computer. May I buy the computer?	Passive voice: MAY BE The computer may be bought by me. The computer may not be bought by me. May the computer be bought by me?
Active voice: MIGHT Guests might play chess. Guests might not play chess.	Passive voice: MIGHT BE Chess might be played by guests. Chess might not be played guests.
Active voice: SHOULD Students should study all lessons. Students should not study all lessons. Should students study all lessons?	Passive voice: SHOULD BE All lessons should be studied by students. All lessons should not be studied by students. Should all lessons be studied by students?
Active voice: MUST You must learn the test-taking strategies. You must not learn the test-taking strategies.	Passive voice: MUST BE Test-taking strategies must be learnt by you. Test-taking strategies must not be learned by you.
Active voice: OUGHT TO They ought to take the examination.	Passive voice: OUGHT TO BE The examination ought to be taken by them.

Passive voice of imperative sentences

                               (command and request)

A sentence which expresses command or request or advice is called imperative sentence.

For example,

      Open the door.
      Turn off the television.
       Learn your lesson.

For changing these sentences in to passive voice, auxiliary verb “be” is used. The word “Let” is added before sentence in passive voice. Auxiliary verb “be” is added after object in sentence in passive voice. Main verb (base form) of imperative sentence is changed to 3rd form of verb (past participle) in passive voice. For best understand read the following examples.

Examples 

Passive voice of “Imperative Sentences”
Active Voice	Passive Voice
Open the door.	Let the door be opened.
Complete the work.	Let the worked be completed.
Turn off the television.	Let the television be tuned off.
Learn your lesson.	Let your lesson be learnt.
Kill the snake.	Let the snake be killed.
Punish him.	Let him be punished.
Speak the truth.	Let the truth be spoken.
Help the poor.	Let the poor be helped.
Revise your book.	Let your book be revised.
Clean your room.	Let your room be cleaned.

Sentences which cannot be changed into passive voice

Transitive and intransitive verb

A verb can be either transitive or intransitive. A transitive verb needs an object (in sentence) to give complete meaning while intransitive verb does need an object (in sentence) to give complete meaning. 
For example,

Transitive verb.
      He sent a letter.
  (Send is a transitive verb and it needs an object i.e. letter to express full meaning.)

Intransitive Verb.
       He laughs.
      (Laugh is an intransitive verb and it does not need object for expressing full meaning.)
    e.g. Sleep, go, reach, sit, die, are examples of intransitive verbs.
 Intransitive verb cannot be changed into passive voice
The sentences having intransitive verbs (belonging to any tense) cannot be changed into passive voice. The reason is that there is not any object in such sentences and without object of sentence passive voice is not possible.

A sentence can be changed into passive voice if it has subject and object. Sometimes subject may not be written in passive voice but it does not mean that it has no subject. Such sentences have subject but the subject is so common or familiar or known that if even it is not written in passive voice, it gives full meaning.
For example
Cloth is sold in yards.   

The following tenses can also not be changed into passive voice.

1. Present perfect continuous tense
2. Past perfect continuous tense
3. Future continuous tense
4. Future perfect continuous tense