(you / eat lunch yet)?

Answer:

Have you eaten your lunch yet?

Present Perfect:

Если в предложении есть слова: ever, never, just, already, yet, for, since тогда это Present perfect.

Present perfect образуется при помощи have/has и третьей формы глагола.

Present perfect:

I have done You have done

We have done You have done

He

She - has done They have done

It