Again and again the doctor ______the crying girl, but he couldn’t find what was wrong with her.

_____ again and again, but he didn’t tell me the truth.

A. Having been asked 　 B. Being asked

C. He had ben asked 　 D. Though he was asked

________ again and again that repeated advertising increases product sales.

1. A.
   It has proved
2. B.
   That has been proved
3. C.
   It has been proved
4. D.
   That has proved

________ again and again in simple words, the problem seems easier for the child to understand.

1. A.
   Explained
2. B.
   To be explained
3. C.
   Having explained
4. D.
   Explaining

________ again and again, but he didn't tell me the truth．

1. A.
   Having been asked
2. B.
   Being asked
3. C.
   He had been asked
4. D.
   Though he was asked