You use whether when you are talking about a choice or doubt between two or more alternatives.
例句
To this day, it's unclear whether he shot himself or was murdered...至今尚不清楚他究竟是飲彈自殺還是被謀殺。Whether it turns out to be a good idea or a bad idea, we'll find out...它到底是個好主意還是壞主意我們很快會見分曉。
CONJ-SUBORD
無論;不管
You use whether to say that something is true in any of the circumstances that you mention.
例句
This happens whether the children are in two-parent or one-parent families...不管孩子是生活在雙親還是單親家庭，這種情況都會發生。Whether they say it aloud or not, most men expect their wives to be faithful.大多數男人還是希望他們的妻子對自己忠誠，不管他們有沒有將這一想法大聲說出來。
英漢詞典釋義
conj.
是否
She was in doubt whether she was right.她對她是否正確拿不準。