Future perfect by 8 o’clock, he (finish) his work. pupils (leave) the classroom by the end of the hour. she (go) home by next month. we (return) from the excursion by eight o’clock in the evening. (buy / they) the new flat by december? the sun (not / rise) by 5 o’clock in the morning. (you/finish) the cleaning by 3 o’clock?

By 8 o’clock, he will have finished  his work.
Pupils will have left the classroom by the end of the hour.
She will have gone home by next month.
We will have returned from the excursion by eight o’clock in the evening.
Will they have bought the new flat by December?
The sun will not have risen by 5 o’clock in the morning.
Will you have finished the cleaning by 3 o’clock?