Question 21: Everybody is tired of watching the same commercials on TV every night, ……… ?

The subject is the pronoun “anyone, anybody, no one, nobody, someone, somebody, everyone, everybody, none of, neither of,” then the question tag uses “they”.

The main verb is “is” in the affirmative form => the verb in the question tag is “aren’t” in the negative form.

Everyone is tired of watching television commercials every night, isn’t it?