①you and I
②he and I
③you and he
④you, he and I
⑤you, they and we(情况多)
① 代替this, that
Thats a book, isnt it ?
---Someone is coming. Who can it be ?
---It may be Jack.
Its a lovely baby. Is it a boy or a girl?
Its 20 miles to (from) Paris.
3、简略回答中用so, not, it 的情况
think, hope, believe, Im afraid, It seems (appears), etc.
---Is it true that he had a heart attack?
---Im afraid so. / I believe so. / It seems so.
---Has Anne got into university?
---Im afraid not. / I think not. / It seems not.
believe, think, suppose, expect, etc
I dont believe so. / I dont think so.
④do代替上下文动词，并且表示一个已完成的动作时，do后常用so / it:
---Please lay the table.
---I’ve just done so (it).