unit 2 healthy eating section b learning about language 题组ⅰ ⅰ.单项填空 1. —sorry, professor smith. i didn’t finish the paper yesterday. —oh, you _________ have done it as yesterday was the deadline. a. must b. mustn’t c. should d. shouldn’t 2. shopping online can save much time as you _________ go to a shop or walk around crowded shopping centers. a. don’t have to b. ough
