In this tense with — shall or will + have been + first form of verb & ing is used. For showing time — Since or for is used.
Since is used for a point of time & For is used for duration of time i.e. Since morning, For two hours.
- We shall have been living here for the last two years.
- The boys will have been making a noise since 1 p.m.
- You have been doing your job for three years.
In these sentences with ‘shall or will + have + not + been + first form of verb & ing is used. For showing time — Since or For is used.
- I shall not have been reading my book for two hours.
- You will not have been singing since morning.
- They will not have been doing their work since morning.
In these sentences— shall or will is used before subject.
And – have + not + been + first form of verb & ing is used.
To express time ‘Since’ or ‘for’ is used.
- Shall we have been playing a match since morning?
- Will you have been taking this medicine for a week?
- Will he have been staying with you for a year?
Similarly in interrogative negative sentences ‘shall or will’ is used before subject and not & have been is used before first form of verb and ‘ing’ in the sentence.
To express time ‘For’ or ‘Since’ is used.
For Example :
- Shall we not have been entertaining the guests since morning?
- Will you not have been flying kites since morning ?
- Will the birds not have been flying in the sky for two hours?