i got close enough to hear them speaking Chinese,and i said"ni hao"just a

问题描述:

i got close enough to hear them speaking Chinese,and i said"ni hao"just a
I got close enough to hear them speaking Chinese,and I said “Ni Hao ” just as I ____ do in China.
A.must B.might C.can D.shoul
请问C 和D项为什么不对呢?

时态上不合适吧,二来语气上也不对.此处只是表示“可能会有的反应”