If students want to improve their performance in class, I would suggest the following two ways. First of all, ask questions more frequently, especially the professors. When a student confronts with tough math problems after the new class and cannot figure them out individually, he could try to contact with the professor to explain the concept as well as several solutions to the question. Secondly, practice often. As an old Chinese saying tells us, “Practice makes perfect”. For example, if he does more practice in the concept of Newton’s law of motion in physics, he would deeper his understanding of it, as a result, increasing his ability of solving such physical problems. These are two ways I’d like to advise to get better grades.
2、有必要的连接词（but, moreover 之类）；
4、看情况适当使用从句长句（which, who 什么的就算）；