Havingatripabroadiscertainlygoodfortheoldcouple,butitr...

問題詳情：

 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

【回答】

B

知識點：非謂語動詞

題型：選擇題