爷爷用他的折叠刀削了一个苹果。

Grandpa used his ___jackknife to peel an apple.

她在比赛中以一个优雅的屈体跳水动作赢得了高分。

She scored high in the competition with a graceful ___jackknife dive.

由于急刹车，卡车在高速公路上发生了甩尾事故。

The truck ___jackknifed on the highway due to sudden braking.