Question

At the beginning of class, the noise of desks _______could be heard outside the classroom.

1. A.
   opened and closed
2. B.
   to be opened and closed
3. C.
   being opened and closed
4. D.
   to open and close

Answer 1

C
思路分析：句意为：在刚开始上课时，课桌打开和关上的噪声在教室外面就听到。the desk与open和close是被动关系，且表示打开和关上的动作正在进行。故选C。
【点评】本题考查了分词的时态，难度较大。做本题时一定看清修饰和被修饰两者之间是主动关系还是被动关系，且注意此动词表过程还是表正在进行。