is it?

Yes. That's one kind of tag question.

CJ

Thank you for your reply.

I thought it should have been

"So that's why you're all dolled up, aren't you?", said Gordon.

Is this tag question possible too?

No, the last tag is not possible. You can have a positive tag after a positive statement to show interest, surprise or some other reaction. The verb "is" is used because it is the main verb (that's = that is). The verb "are" in the sentence is part of a dependent clause and it is not your main verb.

Hi Despoula,

I used to think that you can only have a positive tag after a positive statement. Could you please provide some more examples?

The tag is negative when the question is positive, and vice versa.

You don't understand, do you?
You understand, don't you?

He's not taking the new job, is he?
He's taking the new job, isn't he?

When you use a positive tag with a positive statement, he can sound threatening: He's taking the new job, is he? (It sound like you're angry about it. It's

"So that's why you're all dolled up, aren't you?", said Gordon.

Is this tag question possible too?

No. That's (that is) contains the main verb is. you're (you are) is within a subordinate clause, so it is not available for use in a tag.