.一、引出开头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