To double-check is to look at something again so you can be completely sure it is right, safe, or still there. You already checked once; now you check the same thing a second time — the lock, the spelling, the numbers, whether the passport is in the bag.

To double-check is double-check 就是 to look at something again把一樣東西再看一次， so you can be completely sure讓你能完全確定 it is right, safe, or still there它是對的、是安全的、或還在原位。 You already checked once你已經查過一次； now現在 you check the same thing a second time同一件事再查第二次—— the lock門鎖、 the spelling拼字、 the numbers數字、 whether the passport is in the bag護照在不在包包裡。

It does not mean you check two different things, and it does not mean you are bad at checking. Careful people double-check.

It does not mean它不是說 you check two different things你查了兩樣不同的東西， and it does not mean也不是說 you are bad at checking你不會檢查。 Careful people謹慎的人 double-check都會 double-check。

You can double-check a fact, a door, a list, or someone else’s work (kindly, not as a scolding). The word is friendly and everyday: home, school, and offices all use it. In Taiwan workplaces you will also hear the English “double check” dropped into a Mandarin sentence. “Check twice” is almost the same idea, but double-check is the set phrase people reach for.

You can double-check你可以 double-check a fact, a door, a list一個事實、一扇門、一張清單， or someone else's work或別人做的東西 (kindly, not as a scolding)（帶著好意，不是在數落人）。 The word is friendly and everyday這個字友善又日常： home, school, and offices家裡、學校、辦公室 all use it都在用。 In Taiwan workplaces在台灣的職場， you will also hear你也會聽到 the English "double check"英文的 "double check" dropped into a Mandarin sentence直接嵌進中文句子裡。 "Check twice" is almost the same idea意思幾乎一樣， but double-check is the set phrase people reach for但 double-check 才是大家順口拿來用的固定講法。