そうですね。ジムに行きたい時に限って休館日。。。。ってことがよくありますなぁ
「Unexpected」予想以外
例文⇒It was so unexpected when the library was closed!
「It was so unexpected」予想以外だったんだ「 when the library was closed!」図書館の休館日
「Unbelievable」信じられない/まさか
例文⇒「Unbelievable!」まさか! 「The gym is closed again」また休館日だ「 just when we want to go.」行きたいときだけに
I really wanted to go to the library today, but it was closed when I got there
I wanted to go to the library, but today it was closed for some reason.. :(
In a time of need
直訳すると、「まさかの」はan unexpectedやcouldn't believeになりますが、英語で「図書館へ行ったら、まさかの休館日だった」の「まさか。。」という気持ちを述べたい時、I really wanted to go to the library today, but it was closed when I got thereやI wanted to go to the library, but today it was closed for some reason.と言います。本当に行きたかったけど休館日だった。。みたいな感じです。
でも他の場合、「まさかの」はin a time of needになります。
In case of an emergency, In a time of need
非常の場合には, まさかのときは
ご参考になれば幸いです!