第3题: [单项选择]When you are in your room, leave the door ______so that your visitors do not have to knock. A. open B. opened C. opening D. being open 参考答案:A 答案解析:这是一个固定结构,“leave…+动词”表示“让……保持一种状态”,后面应该用动词原形或形容词形式,如:Leave me alone.让我静一静。这样的结构还有:Let it be.随它去吧。