不慎

tā yī shí bù shèn qiāng zǒu huǒ le

他一时不慎，枪走火了。

He was careless and his rifle went off accidentally.

yī zhāo bù shèn quán jú jiē shū

一招不慎，全局皆输。

One careless move loses the whole game.

tā bù shèn luò rù le xiàn jǐng

他不慎落入了陷阱。

He accidentally fell into the trap.