30. The woman, when ______ how her husband was injured, began to cry.

A. asked　　　　　　 B. to ask　　　　　　　 C. asking　　　　　　　 D. ask

29. -Has Mr. Black decided not to take part in the party?

　 -Yes. But the reason______he refused the invitation is not clear.

A. what　　　　　　　 B. for which　　　　　　 C. with what　　　　　　 D. which

28. Miss White, please keep visitors off the meeting-room. A secret plan______ there.

A. is made　　　　　　　　　　　　　　　　 B. was made　　　　　　　　　　　　　 C. is making　　　　　　　　　　　　　 D. is being made