-----I called you at about half past eight last night but nobody answered. -----Oh, I _____ in my office at that time.
He said that he would write to us but so far we ___________ from him.
__________ good exercise.
I don’t know who invented __________ telescope, but I think it is __________ most useful invention.
Rarely _____________________ .
This is the only way we can imagine _______ the overuse of water in the students’ bathrooms.