一：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...

二：表示好处

1.It has the following advantages.

2.It does us a lot of good.

3.It benefits us quite a lot.

4.It is of great benefit to us.

三：表示坏处

1.It has more disadvantages than advantages.

2.It does us much harm.

3.It is harmful to us.

四：表示重要、必要、困难、方便、可能

1.It is important(necessary，difficult，convenient，possible)for sb.to do sth.

2.We think it necessary to do sth.

3.It plays an important role in our life.

五：表示措施

1.We should take some s.

2.We should try our best to overcome(conquer)the difficulties.

3.We should do our utmost in doing sth.

4.We should solve the problems that we are confronted(faced)with.

六：表示变化

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

2.A great changewill certainly be produced in the world’s communications.

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