参考模板：
1. A number of factors might contribute to the phenomenon, such as……
（这个现象归结于几个原因，例如．．．）
2. The solution to this problem involves many factors.
（问题的解决涉及到几个因素）
3. The change in the attitudes of some people largely results from the fact that...
（一些人态度的变化主要归结于某个事实．．．）
4. We may blame ..., but we can not ignore that the fundamental cause is that……
(我们可能要责备．．．但我们不能忽视的最基本的事实是．．．)
5. Many experts point out that physical exercise contributes directly to a person's physical fitness.
(许多专家指出体育锻炼直接有助于身体健康。)
再给大家分享一些常用句型：
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．．．