初学者英语词汇 1 - 情态动词和助动词

to be able to do somehing, make something, etc.

可以

used to say what is suitable, right, etc., particularly when one is disapproving of something

应该

(auxiliary) used with the past participle form of a verb when forming the passive voice

是

(auxiliary verb) used in forming interrogative and negative sentences

做

used to show that something is very important and needs to happen

必须