Learn Russian: Это мой второй указ: пусть врач будет готов. - This is my second decree: let the doctor be ready.

In English, 'let' is an active verb that takes an object ('the doctor'). In Russian, пусть is just a particle meaning 'let' or 'may'. The real subject of the clause is врач, which takes the nominative case, and its verb is будет (will be).

How does the third-person imperative work in this sentence?

You form it by using the particle пусть followed by the subject and a verb in the present or future tense. Here, we use the future tense verb будет to say 'let him be' or 'have him be' ready for whatever the decree requires.

Why use the short adjective готов instead of the full form готовый?

Short adjectives like готов are used when describing a temporary state or a state tied to a specific situation. They act as the predicate of the sentence and are very common with the verb быть (to be), whereas готовый would describe a permanent characteristic.

Could I use пускай instead of пусть in this sentence?

Yes, пускай врач будет готов means exactly the same thing. Пусть is slightly more neutral and common in formal contexts like a decree, while пускай has a slightly more conversational feel, but both are grammatically correct here.