Question Tags

NEGATIVE SENTENCE	AFFIRMATIVE QUESTION TAG
You aren´t nervous,	Are you?
The Changing of the Guard doesn´t take place every day,	Does it?
You can´t go out tonight,	Can you?
They didn´t like the book,	Did they?

AFFIRMATIVE SENTENCE	NEGATIVE QUESTION TAG
Mary lives in London.	Doesn´t she?
We know when Mary is at home..	Don´t we?
Big Ben is a Clock Tower,	Isn´t it?
We can go to Scotland by plane,	Can´t we?
He lived in Lisbon,	Didn´t he?

1      - We use

a)    Negative question tags with affirmative sentence.
b)    Affirmative question tags with a negative sentence.

2 – We usually use
a)    The auxiliary verb To do in question tags
Except

b)    When the main verb in the sentence is the verb To be or a modal verb.
3. The verb of the question tag must be in the same tense as the verb in the sentence.

4 . Notice that the meaning of yes and no in the answers to question tags:

E.g.: – You aren´t nervous, are you?
- Yes. (= I am nervous)
- No. (= I am not nervous)
5. Exception:

E.g.: I am your friend, aren´t I?