"jackknife" in Chinese (Simplified)
折叠刀（车辆）急弯折叠屈体前翻（跳水动作）
Definition
Jackknife 是一种刀刃可以折叠进刀柄的折叠刀。也可指跳水时腰部弯曲、或车辆（如卡车与拖车）在事故中急剧折弯。
Usage Notes (Chinese (Simplified))
名词主要指折叠刀。作动词常用于描述卡车等车辆在事故中急剧折叠（如“the truck jackknifed”）。体育中专指一种跳水动作。日常生活中不常见，主要出现在上述语境。
Examples
He always carries a jackknife in his pocket.
他总是口袋里带着一个**折叠刀**。
The diver did a perfect jackknife off the board.
跳水运动员从跳板上做了一个完美的**屈体前翻**。
The truck began to jackknife on the icy road.
卡车在结冰的道路上开始**急弯折叠**。
My dad showed me how his old jackknife works.
我爸给我展示了他那个旧**折叠刀**是怎么用的。
Did you see the truck jackknife on the highway this morning?
你今天早上看到卡车在高速公路上**急弯折叠**了吗？
He nailed the jackknife in practice today — the coach was impressed.
他今天训练时完美做出了**屈体前翻**，教练都很惊讶。