脊柱化脓性骨髓炎好发于（）
A.儿童期
B.少年期
C.成人期
D.老年人
E.无差别
参考答案：C
— What do you think we can do for our aged parents?
— You _____ do anything except to be with them and be yourself. [ ]
A. don't have to
B. oughtn't to
C. mustn't
D. can't
柏拉图的代表作是：（）。
