问题补充：
--Mum, can I wear my jeans to school?
--No, you wear school uniforms. That’s the school rule.
A. can
B. may
C. can’t
D. have to
答案：
A. can
B. may
C. can’t
(答案→)D. have to
解析：A. can能够 B. may可能C. can’t不可能D. have to不得不，必须；句意：妈妈，我能穿我的牛仔裤去学校吗？不行，你必须穿校服。那是学校的规定。故选D
