The question arises as to whether or not he knew of the situation.

　　問(wèn)題是，他對局勢是否了解。

　　We're debating whether or not to go skiing this winter.

　　我們盤(pán)算著(zhù)今年冬天是否去滑雪。

　　It remains to be seen whether or not this idea can be put into practice.

　　這一想法能否付諸實(shí)踐還有待于觀(guān)察。