It was some time _______ I realized the truth.
He has given me so much help that I really wanted to do something for him ________.
Mr. Li is absent today. What do you consider ________ to him?
The reason ________ he refused to attend the meeting was that they didn’t give him an invitation earlier.
Our English teacher requested that the homework ________ tomorrow morning.
Smoking, which may be ________ fun for some people, is ________ cause of discomfort for the people around him.