1. It is well-known to us that…（我们都知道……）=As far as my knowledge is concerned, …（就我所知…）
2. Recently the problem of…has been brought into focus. =Nowadays there is a growing concern over ...（最近……问题引起了关注）
3. Nowadays (overpopulation) has become a problem we have to face.（现今，人口过剩已成为我们不得不面对的问题）
4. Internet has been playing an increasingly important role in our day-to-day life. It has brought a lot of benefits but has created some serious problems as well.（互联网已在我们的生活扮演着越来越重要的角色，它给我们带来了许多好处但也产生了一些严重的问题）
5. With the rapid development of science and technology, more and more people believe that…（随着科技的迅速发展，越来越多的人认为……）
6. It is a common belief that…=It is commonly believed that…（人们一般认为……）