原因阐释段

　　示例一

　　① There are many reasons responsiblefor this phenomenon/case/instance and the following are the typicalones.

　　② The first reason is that___(理由一).

　　③ Thesecond reason is that___(理由二).

　　④ The thirdreason is that/A case in point is that/The typical example isthat___(理由三).

　　示例二

　　① There are manyreasons to explain/explaining the effect/phenomenon/case/instance.

　　② The most contributing oneis/the main reason is no other than___(理由一).

　　③ What is more,____(理由二).

　　④___(理由三)also play a role in thiscase.