_____time goes by, my grandfather’s memory seems to get worse and worse.
---I’m sorry to have _________ much of your spare time. ---That’s OK, and I am glad to help you.
Not until Mr. Smith came to China ___ what kind of a country she is.
Mr. Smith approved _______ the company.
When I went in, they were ____ in a heated discussion.
When I was about to go out, something unusual _______ my attention.