Having a trip abroad is certainly good for the old couple,but it remains____ whether they will enjoy it.(NMET2002)

问题描述:

Having a trip abroad is certainly good for the old couple,but it remains____ whether they will enjoy it.(NMET2002)
A.to see B.to be seen
C.seeing D.seen
为什么选B?

B选项是将来时的被动,说明出国旅游对于老夫妇是否有利这一点需要等他们旅游完才能知道,这件事还没发生.