During conversation it is common to make a statement and then ask for confirmation. For example, in the sentence ‘It is very hot, isn’t it?’ we make a statement and then ask for confirmation. Here the later part (isn’t it?) is called a question tag.

In question tags we use the following patterns:

Auxiliary + n’t + subject (If the statement is positive)
Auxiliary + subject (If the statement is negative)

Examples are given below:

You are coming, aren’t you?
He is your friend, isn’t he?
It is raining, isn’t it?
She can speak English, can’t she?
John broke the window, didn’t he?
You aren’t coming, are you?
He isn’t your friend, is he?
She can’t speak English, can he?

Note that the subject of a question tag is always a pronoun, and not a noun.

John is your friend, isn’t he? (NOT …isn’t John)
Alice is a doctor, isn’t she? (NOT …isn’t Alice)

Note the special cases given below:

I am right, aren’t I? (NOT …amn’t I?)
Let’s go for a walk, shall we?
Wait a minute, can you?
Have some coffee, will you?
There is a library in that street, isn’t there?
There are some boys in your class, aren’t there?

Short answers

Short answers to questions beginning with an auxiliary verb have the following structures:

Yes + pronoun + auxiliary
OR
No + pronoun + auxiliary +n’t (not)

Are you coming with us? Yes, I am. OR No, I am not.
Can you drive a car? Yes, I can. OR No, I can’t.
Does he work? Yes, he does.
Did he say anything? No, he didn’t.

Agreements with affirmative sentences are made with ‘yes + pronoun + auxiliary’.

She is a good girl. Yes, she is.
He looks honest. Yes, he does.

Agreements with negative statements are made with ‘no + pronoun + auxiliary + n’t/not’.

He isn’t very intelligent. No, he isn’t.
She doesn’t like fish. No, she doesn’t.
They didn’t play well. No, they didn’t.