Imperative sentences should be quick! Be a verb

Hello! Let me briefly talk about your question.

The so-called imperative sentence is a sentence used to express orders, requests, advice, warnings, prohibitions, etc.

Generally speaking, the subject is omitted and the predicate is based on the verb prototype.

Why don't you use are when you say be verb? This is because you haven't figured out the meaning of the imperative sentence. According to you, if we don't omit the subject, it is that you are fast! In this case, the meaning of the sentence will be stale, and the correct extension sentence should be you must quick! The reason why the be verb uses the prototype is actually not influenced by the subject, but determined by necessity.

I hope my answer can help you!