名词 jackknife:

1. a large knife with one or more folding blades

2. a dive in which the diver bends to touch the ankles before straightening out

动词 jackknife:

1. dive into the water bending the body at the waist at a right angle, like a jackknife

jackn.千斤顶；插座；船首旗；男人；公畜vt.用千斤顶顶起；抬高n.杰克（男子名）n.扑克牌里的Jn.水手；侍者jack-表示"公的"；"雄的"； pref.；表示"公的"

before one can say Jack knife马上；立即

before you could say Jack knife马上；立即

before you can say Jack knife马上；立即

before one could say Jack knife马上；立即