选择恰当的句子补全对话。 A:Can I help you? B:Yes,please. ____ This yellow dress is pretty.How much is it? A:It's forty yuan. B:It's cheap. ____ A:Sure!Here you are. B: ____ A:Do you like that red one? B: ____ A:It's ninety yuan. B: ____ A.It's too big. B.Can I try it on? C.How much is it? D.I want to buy a dress. E.Oh,it's too expensive for me.