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

　　問題是，他對局勢是否了解。

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

　　我們盤算著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踐還有待于觀察。