问题
If you are in any doubt as to _____ you should be doing these exercises, consult your doctor.
A:that
B:which
C:what
D:whether
B:which
C:what
D:whether
正确答案是：
同类题型
The geography teacher told the pupils that light ____ faster than sound.
He did not regret saying what he did but felt that he _____ it differently. [ ]
_______ you come to my party tonight— Sorry, I can’t. I have to do my homework.
ur hope that we will play a greater role in the market place and, ,supply more jobs.