开篇句型：
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 …