/ˈweðə(r); US ˈhweðər ||; ˈhwɛðɚ/conj 1 (used after verbs like ‘ask’, ‘doubt’, ‘know’, etc) if （用于ask、doubt、know等动词后）是否: He asked me whether we would be coming to the party. 他问我，我们会不会参加那个聚会。
2 used for expressing a choice or doubt between two or more possibilities （用于表示两个或以上可能性之间进行选择或犹豫不决）: I can't make up my mind whether to go or not. 我无法决定去还是不去。 ☞ Whether and if can both be used in sense 1. Only whether can be used before ‘to’ + verb Have you decided whether to accept the offer yet? Only whether can be used after a preposition the problem of whether to accept the offer. 表达第1义用whether或if均可。在to加动词之前只可用whether：Have you decided whether to accept the offer yet?你决定接受那建议没有？在介词后只可用whether：the problem of whether to accept the offer是否接受提议这个问题。
whether or not used to say that sth will be true in either of the situations that are mentioned （用于表示某事在所提及的两种情况中都会是真的）:
We shall play on Saturday whether it rains or not. 星期六下雨不下雨，我们都会比赛。Whether or not it rains, we shall play on Saturday. 无论是否下雨，星期六我们都会比赛。