Taking a trip abroad is certainly good f
问题:
Taking a trip abroad is certainly good for old couples, but it remains ____ whether they will enjoy it.
A.to see
B.to be seeing
C.to have seen
D.to be seen
Taking a trip abroad is certainly good for old couples, but it remains ____ whether they will enjoy it.
A.to see
B.to be seeing
C.to have seen
D.to be seen