Question

He left the key ______ he had been an hour before.

A．what

B．that

C．where

D．which

Answer 1

C

试题分析：考查状语从句。句意：他把钥匙忘记在了一小时前他所在的地方。本句中的where he had been an hour before在句中做地点状语，修饰动词left the key。故C正确。
点评：首先要搞清楚状语从句的作用，状语从句要在句中修饰动词或者整个谓语部分，状语从句的考查集中在连接词的选择上，要和句意相结合。