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。Whether 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 farmers as well.
2.There is no denying the fact that…
There is no denying the fact that air pollution is an extremely serious problem：the city authorities should take strong measures to deal with it.
3.As is known to all，…
As is known to all，fake and inferior commodities harm the interests of consumers.(=do a lot of harm to the interests of consumers)
4.More and more people are realizing the importance of …
Today an increasing 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 mentioned above，we can see clearly that violence on TV has (a) great influence on young adults‘ behaviour.(或 teenagers’ behavior 或 youngsters‘ behavior)