导语：在课本上多积累句型的'同时，也要注意课外积累英语写作的句型哦。
一、原因
1.A number of factors are accountable for this situation.
A number of factors might contribute to (lead to )(account for ) the phenomenon(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 ely results from the fact that...
6. We may blame ...,but the real causes are...
7. Part of the explanations for it is that ...
of the most common factors (causes ) is that ...
her contributing factor (cause ) is ...
aps the primary factor is that …
the fundamental cause is that ...
二、比较
advantage far outweigh the disadvantages.
advantages of A are much greater than those of B.
3.A may be preferable to B, but A suffers from the disadvantages that...
is reasonable to maintain that it would be foolish to claim that...
all the disadvantages, it has its compensating advantages.
anything else, it has its faults.
7.A and B has several points in common.
8.A bears some resemblances to B.
ver, the same is not applicable to B.
10. A and B differ in several ways.
11. Evidently, it has both negative and positive effects.
12. People used to think ..., but things are different now.
13. The same is true of B.
14. Wondering as A is ,it has its drawbacks.
15. It is true that A ... , but the chief faults (obvious defects )are ...