距离2016年12月英语四级考试还有两个多月的时间，新东方在线英语四级频道特为大家整理了英语四级作文常用句型，方便大家复习时参考，预祝大家取得好成绩!
3-1-1. 基本原因 --- 分析某事物时, 用此句型说明其基本的或者多方面的原因.
[1]. The answer to this problem invovles many factors. For one thing... For another...... Still another ...
[2]. A number of factors , both physical and psychological affect .... /both individual and social contribute to ....
