The comparative structure is an important point in Chinese language that the foreigners who learn Mandarin in China should master. The first form is the sentence with 比. The 比 sentence is used to show the difference between two persons or things through a comparison in the pattern “A比B…”. And you should know the following part should be an adjective like飞机比汽车快.

You need to pay more attention to different situations when you use such stricture. In a 比sentence, if the predicate is an adjective, it cannot be preceded by such adverbs as 很、真、非常, etc. Accordingly, we cannot say 飞机比汽车快 as飞机比汽车很快. If the adverb has a complement of state, 比 can be placed either before the verb or before the complement. For instance, we can say both 他比我考得好 and 他考得比我好.

Sometimes, we may intend to tell the difference of things in a rough manner. In this case, we should use 一点儿 and 一些 for limited difference. And for the huge difference, we should use 多, 得多 and 多了. If you study Mandarin online, you may often see the examples like 上海冬天是不是比北京暖和一点儿？这件比那件贵多了and 他跑得比我快多了.

Much attention should be paid to the negative form. Usually, the negative form for 比is 没有, but not 不比, which is often wrongly understood by the learners. Therefore, the negative form of  飞机比火车快 should be 火车没有飞机快. The structure “A 不比B…” is only used to express disagreement or refutation. For instance, A：我看你比麦克高。B：我不比他高。我们俩差不多高.

Another form that the students who learn to speak Chinese should know is A有/没有B（这么/那么）+adjective, in which the verb 有may be used to denote “as…as…”. The affirmative form is normally used in questions or rhetorical questions while the negative form is used mostly in indicative sentences like他有你（这么）高吗？and他没有我（这么）高.