10. since 句型：It is/ has been +时间段+ since…+一般过去时. (到目前为止）干某事有多长时间了It was + 时间段 + since +过去完成时 （到过去某时间为止）干某事有多长时间了 Sb/ sth.+ 现在完成时+since+ 过去时。。（ 注意从句的谓语动词是否延续）Eg: It is about ten days since he came back from abroad.It was days since I had left there.比较一下：He has written to me frequently since I fell ill. 自从我生病以来，他就经常给我写信。He has written to me frequently since I was ill. 自从我病愈以来，他经常给我写信。11. when 句型：It will be +时间 + when +一般现在时 当某事发生时，时间将会是。。。It was +时间 + when+一般过去时 当某事发生时， 时间是。。Eg: It will be midnight when they get there .It was 1949 when new China was founded.13、强调句型：(1) It is ／was ＋被强调部分＋that（who）．．． 例：It was I who wrote to my uncle yesterday．是我昨天给我叔叔写信的。(2) Is/was it + 被强调部分 + that (who) ...例：Was it your brother that you met in the street?在街上你遇见的是你兄弟吗？(3) Where/who/what/how… + is/was it that ...例：How is it that you will go to visit her tomorrow?明天你究竟怎样去看望她？宾语从句中的强调句Tell me who it was that you met in the street yesterday afternoon?(4) do +谓语动词（强调谓语）例：They do know the place well. 他们的确很熟悉那个地方。(5) not until 的强调句型： It + be not until… that…14、用于表示过去未实现的希望和计划的句型：(1) should like to/ would like to/ would love to have done sth.例：You should like to have written to your mother.你本应当给你母亲写信。(2) expect, intend, hope, mean, plan, promise, suppose, think, want, wish ．．．常用过去完成时态,在这些词后接宾语从句或者接不定式的一般形式；或者用一般过去时态后面接不定式的完成形式例：I had wanted to helped you with your homework but I couldn't spare any time.= I wanted to have helped ….(3) wish that …had done sth.表示过去未曾实现的愿望．例：I wish he had been here yesterday. 要是他昨天在这儿就好了。(4) 情态动词 should ,would, could, might, ought to 等后接不定式的完成时，表示should have done =ought to have done 本应该做而没做would have done = 本来就会去做某事而没做could have done = 本可以做某事而没做might have done 本可以做而没做例：They ought to have apologized. 他们本该道歉的。
