问题
Can you give me some advice about the design— I think it should _______ to all ages andsocial groups.
A:why we cry when we are hurt
B:why we cough when we suffer from a cold
C:why we smile when we see someone else smile
D:fit
B:why we cough when we suffer from a cold
C:why we smile when we see someone else smile
D:fit
正确答案是：
