In the first paragraph, writers often use 2 long sentences to complete it. The former one is to rephrase the question and give related information about the question and then in the latter one they must state their standing to illustrate how they would like to approach this issue as a whole.
"To sum up, teachers are who have more knowledge and social experience than students, in this case, they can not just teach nothing but books, in other words, to make sure every student could learn optimistically, that can not be emphasized enough."
Here is my ending
To sum up, teacher are often more knowledgeable than students, so they may play a vital role in passing on knowledge in the textbooks to students. More than that, teachers can work as a good mentor to help students think in different ways. They are equally important in my opinion.
In addition: I am not a native speaker and I am a lifelong teacher who is all the time learning.