1. It is important ____________ the situation all over the world.

   A. study             B. to study          C. studies           D. to be studied   

2. It is kind  __________ him to help me __________ the difficult problem.¡¡

A. of, solve       B. for, solve        C. of, solving        D. for, solving

3. Do you know who ___________ with at eight yesterday?

A. he is talking       B. was he talking    C. he was talking     D. is he talking

4. Mr. Liu was telling his son that the moon ______ around the earth at this time last Friday evening.

    A. went             B. has gone        C. had gone         D. goes