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．．．
6）We have good reason to believe that．．．
7）It has the following advantages．
8）It does us a lot of good．
9）It benefits us quite a lot．
10）It is beneficial to us．
11）It is of GREat benefit to us．
12）It has more disadvantages than advantages．
13）It does us much harm．
14）It is harmfulto us
15）It is important（necessary，difficult，convenient， possible）for sb．to do sth．
