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 ..., ...