虚拟语气的用法

1、                          if条件句（v.）        主句（v.）

与现在相反          did/were            would/could/should/might+do

与过去相反          had done           would/could/should/might+have done

与将来相反          did/were            would/could/should/might+do

                          were to do

                          should(do)

2、变成一般疑问句时，可把现成助动词（be、情态、构将、构完）提前，再去掉if

1、语气(虚、实)的交错

You reminded me of the meeting,otherwise,I would have forgotten it.

                                      真实       --（否则）--    虚拟

虚拟：If you hadn't reminded me of the meeting,I would have......

2、时态上的交错

If I had worked hard before,my English would be good.

                                   过去    现在

3、wish that+宾           与现在相反 did/were  I wish I were a bird.

      I  I  希望...          与过去相反had done  I wish I had got up ealier.

    if only                 与将来相反     do        I wish I could live on the moon.

              要是...就好了

4、It's (high) time that......是时候做...了

                             sb. did sth.

                             sb. should do sth.

=It's time for sb. to do sth.

5、as if/though   仿佛，好像

     真实（ 可能是事实  ）It looks as if it's going to rain.

     虚拟（不可能是事实）when a stick is in the glass with water, it looks as                                      if it were broken.

与现在相反did/were 

与过去相反had done

6、could have done 本可以做...