问题补充：
--- I bring you all the magazines right now?
--- No, you don’t have to, but you give them to me tomorrow.
A. May; can
B. Should; must
C. Can; can
D. Must; had better
答案：
A. May; can
B. Should; must
C. Can; can
(答案→)D. Must; had better
解析：句意：--我必须马上还给你所有的杂志吗？--不，你不必，但是你最好明天给我。根据答语，不，你不必。可以判断问句问的必须马上还吗？所以要用must。had betterdo最好做某事。故选D.
