1. 选D。what made matters worse 是主语从句(注意其后有谓语动词was)，相当于 the thing that made matters worse。
2. 选A。what 引导的是表语从句，相当于 the thing that it takes to do anything well。
3. 选C。that 引导的是一个主语从句，句首的it为形式主语。
4. 选 C。答句为省略句，其完整形式为 I was trying to prove to the police where I was last night，在此 where 引导的是一个宾语从句。类似地，下面选 C：
