tag questions - special features

positive statement - positive tag

We sometimes use a positive tag with a positive statement when we want to express surprise or particular interest:

I shall be staying at my favourite hotel - the five-star hotel in Windsor. ~ Oh, you've stayed there before, have you?

And I'm having supper there with the Australian tennis ace, Lleyton Hewitt. ~ Oh, so you know Lleyton Hewitt, do you?
imperative sentences and let's

After imperatives, we sometimes add will you? or won't you? when we want people to follow our advice:

Don't stay there long, will you?

And do take care, won't you?
After let's we sometimes add shall we? when we are making a suggestion:

Let's have buttered scones with strawberry jam for tea, shall we?

Omission of pronoun subject and auxiliary verb
In very informal speech, we sometimes leave out pronoun subjects, auxiliary verbs and verb to be in the statement. Compare the following:

Awful weather, isn't it? (= It's awful weather, isn't it?)

Keeping well, are you? (=You're keeping well, are you?)

Nobody at home, is there? (=There's nobody at home, is there?)