根据具体情况选择集体的方法,作差法证明中尽量化简成几个式子的乘积,然后判断式子的正负,作商法证明中化简结果要与1比较大小。  四、假设法  假设法是先假定某些条件,再进行推理,若结果与题设现象一致,则假设成立,反之,则假设不成立。

I like to see movies so much. When I have time, I spend most of the spared time on watching classic movies. Though some people believe that it is a waste of time to spend time on this amusement, actually, they are wrong. Watching movies is a good way to broaden our vision. A good movie always shows something about culture or social problems, so as to catch more people’s attention and help them to think about the problem. We can perceive the world through excellent movies. When culture shock happens, we will considerate what we always believe is right needs to be changed. Our viewpoint about the world gets improved and helps us to be a better man. Reading books may be boring for some people, while watching movie is a fun way to gain knowledge.