Please excuse me _______ your letter by mistake.
—An ant has two stomachs—one for itself, one for others. —Really? Quite interesting. I ________ anything about it.
Noise is unpleasant, ________ when you are trying to sleep.
—Was ________ problem solved?—We were trying to think of ________ way out, but it was difficult to find one.
The couple have decided to________buying a car until their economic condition becomes much better.
________Chinese culture with overseas cultures is a challenging job, but you will learn a lot from it.