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 ……， ……