Write a tag for each sentence . 1) they are having lunch, ................? 2) they have lunch,..............? 3) there are apples in the basket,............? 4) he isn't playing chess,...............? 5) he doesn't play chess,................? 6) there is a bag under the chair,.............? 7) we have seven lessons on Monday,......? 8) you are thinking about the letter,..........? 9) you think I am wrong,.........? 10) you think he is right,..............?

They are having lunch, aren’t they?
(В Present Continuous: вспомогательный are, отрицательная форма в хвостике.)

They have lunch, don’t they?
(В Present Simple: смысловой have, значит хвостик с do.)

There are apples in the basket, aren’t there?
(Оборот there are → хвостик aren’t there.)

He isn’t playing chess, is he?
(Есть isn’t → в хвостике утвердительное is he.)

He doesn’t play chess, does he?
(Есть doesn’t → в хвостике does he.)

There is a bag under the chair, isn’t there?
(Оборот there is → хвостик isn’t there.)

We have seven lessons on Monday, don’t we?
(В Present Simple: have как смысловой глагол → хвостик с do: don’t we.)

You are thinking about the letter, aren’t you?
(Есть are → хвостик aren’t you.)

You think I am wrong, don’t you?
(Главная часть you think в Present Simple → хвостик don’t you.
То, что дальше I am wrong, на хвостик не влияет.)

You think he is right, don’t you?
(Точно так же: главная часть you think → хвостик don’t you.)