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

A. opened and closed                 B. to be opened and closed 

C. being opened and closed     D. to open and close

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

A. opened and closed     B. to be opened and closed

C. being opened and closed   D. to open and close

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

   A. opened and closed                     B. to be opened and closed

   C. being opened and closed              D. to open and close

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

A. opened and closed　　　　 B. to be opened and closed

C. being opened and closed　 D. to open and close

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