Question

【題目】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】句意：Bob打電話給他的媽媽，告訴她說他進不了房門，因為他把他的鑰匙忘在學校了。根據句意可知，把鑰匙忘在學校（leave）的動作發生在打電話（called）之前，called 是過去時，那么忘記鑰匙在學校leave就是發生在過去的過去，即過去完成時，故選擇A項。