1.…is a very popular topic which is much talked about not only by …but also by …家庭人口多好还是家庭人口少好是一个非常通俗的主题，不仅是城里人，而且农民都经常谈论这个问题。
Weahter a large family is a good thing or not is a very popular topic which is often talked about not only by city residents but by farners as well.
2.There is no denying the fact that…无可否认，空气污染是一个极其严重的问题：城市当局应该采取有力措施来解决它。There is no denying the fact that air pollution is an extemerely serious problem:the city authorities should take strong measures to deal with it.
3.As is known to all,…众所周知，假冒伪劣商品损害了消费者的利益。As is known to all,fake and inferior commodities harm the interests of consumers.(=do a lot of harm to the interests of comsumers)
4.More and more people are realing the importance of …现在越来越多的人认识到法制教育的重要性。为了维护社会治安，我们每人都应该接受法制教育。
Tody an increaasing number of people have realized that law education is of great importance .In order to keep law and order,very one of us is supposed to get(=receive)a law education.
5.From what I have mentioned above we can see clearly that…从上面我所提到的，我们可以清楚地看到，电视暴力对青少年的影响是极其深远的。
From what I have mentoned above,we can see clearly that violence on TV has (a) great influence on young adults’ behaviour.(或 teenagers’ behavior 或 youngsters’ behavior)