The robber had escaped and was nowhere to be found when the police ____

问题描述:

The robber had escaped and was nowhere to be found when the police ____
A. arrived B. had arrived C. belongsD. have arrived
请帮我分析一下,谢了!

答案选 A ;
盗贼“逃跑”在警察“到达”之前,所以“逃跑”用过去完成时(had escaped),“到达” 用一般过去时(arrived);
句子意思:警察到达时,盗贼早已逃跑,到处都没找到.