-what am l supposed to buy for my mother as a birthday gift?-you --- get her a scarf.

问题描述:

-what am l supposed to buy for my mother as a birthday gift?-you --- get her a scarf.
a\ should be supposed to
b\ are supposing to
c\ are supposed to
d\ should suppose to
为什么答案是c
说明理由

填 c.are supposed to
you are supposed to 和问句 what am I supposed to ...对应