第一段一般只写三句

　　第一句：It is widely believed that by many people for some time that ...

　　第二句：One reason they think is that...

　　第三句：The ohter reason they hold is that...

第二段一般只写三句   

　　第一句：While others argue that ...

　　第二句：They maintain that...

　　第三句：They also claim that...

第三段写四句

　　第一句：From what has been discussed above, we may come to the conclusion that ...

　　第二句：On the one hand, ...

　　第三句：On the other hand, ...

　　第四句：Only in this way can we ...