she_____the blackboard before the teacher arrived.A,had cleaned B,cleaned C,has cleaned D,cleans
问题描述:
she_____the blackboard before the teacher arrived.A,had cleaned B,cleaned C,has cleaned D,cleans
答
答案A
这里有两个动作,
1,擦黑板
2,老师到来
我们看先后顺序,这里要表达的是在老师来之前已经擦好了黑板
老师来,是一般过去时态
所以,擦黑板就是过去的过去,就是过去完成时态