The clever boy made a hole in the wall, _______he could see what was going on inside the house.

A. on which                                                     B. at which

C. through which                                             D. in which

The clever boy made a hole in the wall, ________ he could see what was going on inside the building.

    A. on which    B. at which    C. through which    D. in which

The clever boy made a hole in the wall, ________ he could see what was going on inside the building.

1. A.
   on which
2. B.
   at which
3. C.
   through which
4. D.
   in which

The clever boy made a hole in the wall, _____ he could see what was going on inside the house．

A．on which               B．at which          C．through which                D．in which

the clever boy made a hole in the wall, _____ he could see what was going on inside the

  house.

  A. on which      B. at which     C. through which    D. in which