A.

You see someone throwing away a paper bag in a park when there is a litter bin provided not far away. Be critical, but polite.

Excuse me! (I say!) There's a litter bin over there, you know. Why don't you use it? (Can't you see it?) (You shouldn't throw things on the ground like that).

B.

A shopkeeper has just told you that the bottles you have brought back are non-returnable and he won't accept them. Comment on this.

That's a nuisance. So I suppose I'll have to take them home again and throw them away. It would be a lot more sensible if (it used to be more sensible when) the company took the old bottles back. It wouldn't be (wasn't) so wasteful, either.

C1

You have gone into a grocer's shop to buy a number of things:
(a) ask for the things on your shopping list.

Good morning (afternoon, etc.) I'd like 3 lbs of potatoes...

C2.

(b) then ask whether the shopkeeper has something in stock which you cannot see.

Oh, and have you got any...? I can't see it (them) anywhere.

C3.

(c) just before leaving, you remember something else you had forgotten. Ask for it and apologise because the shopkeeper has already added up the bill.

Oh, there's one more thing. I nearly forgot. Could I have... (Give me..., will you)? I'm really sorry.