在句子“我们必须周五前提交报告”中，“must”这个词是一个情态动词。

In the sentence 'We must submit the report by Friday,' the word 'must' is a ___modal ___verb.

像“might”和“can”这样的词是情态动词的例子。

Words like 'might' and 'can' are examples of a ___modal ___verb.

情态动词与另一个动词连用，用以表达可能性或必要性等含义。

A ___modal ___verb is used with another verb to express ideas like possibility or necessity.