Question

 Bob called to tell his mother that he couldn’t enter the house, for he ______ his key at school.

A. had left                       B. would leave               C. was leaving            D. has left

Answer 1

 答案：A

解析：題干意思是：鮑伯打電話給他的媽媽說他不能進房子，因為他把鑰匙忘在學校了。本句中的called標明動作發生在過去，而在電話之前忘記拿鑰匙，所以應用had left表示過去的過去的動作。