Let's go into town.
No,l've got to do this homework .If l go into town , l won't finish it today .
So what?
Well, if l don't finish it today , l won't give it to the teacher tomorrow.
I see - and if you don't give it to her she'll be angry with you.
That's right.
Well, l'll be angry with you if you don't come into town with me.
Oh , no! Look -if l come with you, will you help me later with the homework?
OK - it's a deal!