帮助动词表示需要、可能或愿望的词叫助动词。助动词经常修饰动词或形容词，它的后边不能直接带名词。助动词的否定式是在助动词前边用否定副词"不"。
Verbs that "help" other verbs to express necessity, possibility and willingness are called auxiliary verbs. Auxiliary verbs are often used to modify verbs or adjectives. A noun cannot immediately follow them. They are negated by 不.

助动词有以下几类：
Auxiliary verbs include the following kinds:

1. 表示有某种技能、能力的：
   Those expressing capability:

   能     能够     会

2. 表示可能的：
   Those expressing possibility:

   能  能够  会  可以  可能

3. 表示情理上需要的:
   Those expressing necessity by reason:

   应该  应当  该  要

4. 表示必要的：
   Those expressing obligation:

   必须    得（děi）

5. 表示主观愿望的：
   Those expressing willingness:

   要  想  愿意  敢  肯