A man from the state chu was crossing the river. in the boat, his sword fell into the water by his carelessness. imediately he made a mark on the boat.“this is where my sword fell off.”he said. when the boat stopped, he jumped into the water to look for his sword at the place where he marked the boat. the boat had moved but the sword had not. is this not a foolish way to look for a sword?

从前，一个楚国人在坐船过河时，不小心把他的剑掉入了水中。他马上在船上做了个记号。“这是我的剑掉下去的地方。”他说。船停下来后，他就根据船上的记号跳入水中寻找他的剑。船在移动但他的剑并没有。用这种方式来找剑难道不是非常愚蠢的吗？

刻舟求剑 (kè zhōu qiú jiàn)
【翻译】marking his mark.
【释义】比喻一个人不懂事物已发展变化而仍静止地看问题。
【例句】如果一个人只是刻舟求剑的话，是很容易失败的。
【近义词】守株待兔，墨守成规
【反义词】看风使舵，见机行事