题目内容
Since the front door is locked, why not ____ at the back door? Someone might come out and answer it.
A. to try knocking B. trying to knock
C. to try and knock D. try knocking
【答案】
D
练习册系列答案
相关题目
My colleague has been recovering gradually since the operation, and it wont’ be long ______ he comes back to work.
|
A.before |
B.since |
C.after |
D.when |