请问 感官动词无被动语态这句话对吗?

题目

请问 感官动词无被动语态这句话对吗?
Having a trip abroad is certainly good for the old couple,but it remains____whether they will enjoy it
A to see B to be seen C seeing D seen
应该选什么怎么理解呢

答案

只不过是没有被动形式,意思还是被动的.
这道题选B,remains to be seen是固定搭配,意思为尚待分晓.
不过see倒是有被动语态的.think也是.