一、举例

　　1) A good case in point is ...

　　2) As an illustration, we may take ...

　　3) Such examples might be given easily.

　　4) ...is often cited as an example.

　　二、证明

　　1) No one can deny the fact that ...

　　2) The idea is hardly supported by facts.

　　3) Unfortunately, none of the available data shows ...

　　4) Recent studies indicate that ...

　　5) There is sufficient evidence to show that ...

　　6) According to statistics proved by ..., it can be seen that ...

　　三、开篇

　　1) Many nations have been faced with the problem of ...

　　2) Recently the problem has been brought into focus.

　　3) Recently the phenomenon has become a heated topic.

　　4) Recently the issue has aroused great concern among ...

　　5) Nowadays there is a growing concern over ...

　　6) Never in our history has the idea that ... been so popular.

　　7) Faced with ..., quite a few people argue that ...

　　8) According to a recent survey, ...

　　9) With the rapid development of ..., ...

　　四、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 ...largely results from the fact that...

　　6. We may blame ...,but the real causes are...

　　7. Part of the explanations for it is that ...

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

　　Another contributing factor (cause ) is ...

　　Perhaps the primary factor is that …

　　But the fundamental cause is that