The most pleasant thing of the rainy season is ________ one can be entirely free from dust.

My parents_________ in Hong Kong. They were born thereand have lived nowhere else.

Do you enjoy _____ in this city —Yes, I do.

It’s impossible for us to work out the Math problem in just 10 minutes. It’s too difficult.—You’re right. We can’t be _______ careful while working on it.

The lack of money forced them to________their research.