Usually pilots need about a decade of experience _______ they can be promoted to captain

Why do you like living in the countryside—Because there’s _______ noise and _______ cars there.

During his stay in the USA, Yao Ming said that he would go back to China ______ he was needed.

When I tried to find _________that prevented so many people from taking part in the program, it seemed to me that there were two main reasons.

Why were you upset? The headteacher wasn’t blaming anyone He said things like that could be avoided