Thecleverboymadeaholeinthewall,_?
The clever boy made a hole in the wall, _______ he could see _____ was going on inside house. A. which; what B. through which; what . through that; what D. what; that 【答案】 【解析】
选B throught which, which 引导一个非限定性定语从句,which 代替 a hole； what was going on... what 引导一个宾语从句，在屋外发生了什么