6.A:What shall we do this afternoon?
B:Why not go and collect empty bottles in the park to help save our world?
A:(51)That's a good idea!/Good idea!/Nice idea!!By the way,what shall do with the empty bottles?
B:Let's sell them to the recycling centre.
A:Then we will have some money,won't we?
B:(52)Yes,that's right./Yes,we will..We can use the money to help a boy named Mike.
A:A boy named Mike?(53)What has happened to him?/What's the matter with him??
B:Both his parents died in a traffic accident last month.
A:(54)I'm sorry to hear that./That's a shame..
B:So we can use the money to buy some books and clothes for him.
A:I agree with you.(55)When shall we meet??
B:What about at two o'clock?
A:All right.See you then?