when and where the new hospital will be built___a mystery.

问题描述:

when and where the new hospital will be built___a mystery.
a.to remain
b.remains
c.remain
d.is remaining
为什么?知识点是什么?

主语 医院是单数,动词后面加s
hospital remains a myster 是中心思想.医院留了一个悬念
悬念是, when and where going to built . 什么时间,在哪里建