问题
选择题
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
答案
答案：C
这题考查定语从句：介词+which，句意是：聪明的男孩在墙上打了个洞，通过这个 洞他可以看到大楼里发生的事。选C。