题目

When he  _______ the door, he found his keys were nowhere.                         A. would open           B. opened                 C. had opened           D. was to open 答案：D 解析: 考查非谓语动词。动词不定时的用法。句意为：当他要打开门的时候,他发现他的钥匙不见了。动词不定时表示将要发生的动作。16．-________ are you late today？-Because my bike is broken．（　　）A．WhatB．HowC．WhenD．Why