－Have you seen Mr. Black these days, Jack?－Yes, I met him when I ________ in the street yesterday.

–I feel tired and sleepy. –Why not stop __________?

Don’t throw away the waste paper. It needs           so that it can be reused. 

We’ll do what we can ______ English well this term.

-----Do you remember ______ me somewhere in Shanghai?------Of course. Two years ago.