Question Tags

If you want a confirmation, you can always repeat a statement and say "..., right?":
It's a lovely day today, right?
He is at work, right?

There are, however, the so called tag questions, which are used for the same purpose, and are so popular that they deserve attention. What are they like? A few examples:
You are not busy, are you?
He is coming, isn't he?
Your parents have never been to Asia before, have they?
Pete went to the cinema, didn't he?
These mini questions substitute "right?", and are formed the way you would normally ask the full question, so the form depends on the sentence.

How to ask this question

1. First we take the verb.
If it is to be (am, is, are, was, were) or a modal verb, we repeat it. If the sentence is positive (+), the tag is negative (-) and vice versa:

With all other verbs we use the auxiliary, again paying attention to the negative:

If there is no auxiliary verb in the sentence, and these are only the cases of present or past simple tense, then we add it like this:

2. After that we add the subject. If it is a pronoun, we repeat it, and if not - substitute with a pronoun:

A detailed list of the different tenses, as well as some special forms you can see when you click this table:

Intonation

When one uses these sentences, they are usually asking for confirmation. In this case they are either unsure, or they are almost sure but only need to hear they are right. For example:
1) You'll be at work tomorrow, won't you? (I suppose, but I am not sure. I want you to tell me.)
2) Are you ready with the presentation? The meeting starts in 5 minutes, doesn't it? (I know it starts then, but I am reminding you, to make sure you know it, too.)
In the first case the intonation is interrogative because we really want to know the answer.
In the second case the question is rhetorical and sounds like a statement, and not like a question.

How to reply to such a question

No matter whether the question is negative or positive, the use of "yes" or "no" in the answer depends entirely on the answer; that is, "yes" if it is positive and "no" if it is negative:

"I am late, aren't I?" "Yes, you are."
"I am not late, am I?" "Yes, you are."

"Over 50 people have been interviewed, have they?" "No, they haven't. Only about 10 so far."
"It hasn't been built yet, has it?" "Yes, of course it has. They finished it a few months ago."