表示原因

　　1.A number of factors are accountable for this situation.

　　A number of factors might contribute to (lead to )(account for ) thephenomenon(problem).

　　2. The answer to this problem involves many factors.

　　3. The phenomenon mainly stems from the fact that

　　4. The factors that contribute to this situation include

　　5. The change in largely results from the fact that

　　6. We may blame ，but the real causes are

　　7. Part of the explanations for it is that

　　8. One of the most common factors (causes ) is that

　　9. Another contributing factor (cause ) is

　　10. Perhaps the primary factor is that

　　11. But the fundamental cause is that

　　12. There are three reasons for this.

　　13. The reasons for this are as follows.

　　14. The reason for this is obvious.

　　15. The reason for this is not far to seek.

　　16. The reason for this is that

　　17. We have good reason to believe that

　　例如：

　　There are three reasons for the changes that have taken place in our life.Firstly，peoples living standard has been greatly improved.Secondly，most people are well paid， and they can afford what they need or like.Last but not least，more and more people prefer to enjoy modern life.

　　注：如考生写第一个句子没有把握，可将其改写成两个句子。如：Great changes have taken place in our life. There are three reasons for this.这样写可以避免套用中的表达失误。