He looked hard at the blackboard but could not ----(see) the

问题描述:

He looked hard at the blackboard but could not ____(see) the words clearly
如何确定是否是过去式,
1个回答 分类:英语 2014-10-05

问题解答:

我来补答
see
looked 和 could 都是过去时的表现
再问: 是不是该动作前头有过去式就可以原型。could,should都是对吗
 
 
展开全文阅读
剩余:2000
上一页:质点位移问题