[解析]
W:Tomorrow is Saturday. Should we go shopping in the afternoon? M:Um. Why not go shopping on Sunday? I'd like to relax at home after a week's work. W:All right. Let's go shopping on Sunday morning. M:What do you want to buy? W: I need a dress for that wedding. I'm going to attend. M: I should go shopping too. I need a backpack for a hiking trip. My friends are planning. W:Great.If you help me choose a dress that looks good, I'll help you find a backpack. See you Sunday.