1. —Sorry，Professor Smith. I didn’t finish the assignment 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 center.
A. don’t have to B. oughtn’t to
C. won’t D. mustn’t
