第一类：表示原因

　　1)There are three reasons for this.

　　2)The reasons for this are as follows.

　　3)The reason for this is obvious.

　　4)The reason for this is not far to seek.

　　5)The reason for this is that…

　　第二类：表示益处/害处

　　1) It has the following advantages.

　　2) It does us a lot of good.

　　3) It benefits us quite a lot.

　　4) It is beneficial to us.

　　5) It is of great benefit to us.

　　6) We have good reason to believe that…

　　7) It has more disadvantages than advantages.

　　8) It does us much harm.

　　第三类：表示变化

　　1) Some changes have taken place in the past five years.

　　2) A great change will certainly be produced in the world's communications.

　　3) The computer has brought about many changes in education.

　　第四类：表示重要性

　　1) doing sth. is of utmost importance / should be given priority

　　2) it is admitted that sb. should do

　　3) It plays an important role in our life.

　　第五类：表示措施

　　1)We should take some effective measures.

　　2) It is high time we tried our best to overcome(conquer)the difficulties.

　　3) Great effort is needed to…

　　4) There are several ways to deal with the problem.

　　第六类：表示事实现状(首段常见)

　　1) We cannot ignore the fact that…

　　2) No one can deny the fact that…/There is no denying the fact that…

　　3) indeed /apparently / obviously

　　4) This is a phenomenon that many people are interested in.

　　5)it is true that…

　　第七类：表示比较

　　1) Compared with A，B……

　　2) I prefer to read rather than watch TV.

　　3) There is a striking contrast between them.

　　第八类：表示看法(首段或尾段)

　　1)People have(take，adopt，assume)different attitudes towards sth.

　　2) from my point of view

　　3)People take different views of(on)the question.

　　4)Some people believe that…Others argue that…

　　5) in terms of…谈及..问题时