2018-2019学年度牛津版必修二Unit 1 Tales of the unexplained-grammar课件(43张PPT)
2018-2019学年度牛津版必修二Unit 1 Tales of the unexplained-grammar课件(43张PPT)第2页

past

now

Yesterday , we cleaned the classroom.

Now , the classroom is clean because we have cleaned it.

用法1

强调过去发生的动作对现在产生的结果或影响

现在完成时