Unit 3 A healthy life
grammar

Lead-in  1.It is never too old to learn.
2.It is easy to finish the work in two days.
3.It is no use crying over spilt milk.
4.I found it very interesting to study English.
5.He made it clear that he was not interested in that subject.
6.It was Tom that I saw on the street last night.
7. It was not until yesterday that I met my old friend.
8.It is in a small factory that my brother is going to work.

  it使用方法小结