11. He had been teaching at school for five years when the war broke
out.
12. Hi! What have you been doing here since morning?
13. By the end of this year he will have read about two hundred pages.
14. When did you see him last?
15. Don’t ring me up at 11 o’clock, I will be sleeping.
16. ‘Have you found your note-book?’ ‘No! I am still looking for it. I have
already been looking for it for two hours, but have not found it yet.’
17. They will have been sailing down the river for many hours before
they come to the village.
18. At last the librarian gave me the book which I had been waiting for
during two months.
19. He had been writing the composition for three hours and he said he
would finish it soon.
20. On entering the drawing-room he found that his two friends had up
and were waiting for him.