four-speed

基本解释

By applying a mathematical transform to the coupling control equations about the phonon field and phason field, two standard wave equations and four speeds of wave are founded.
考虑一维准晶体制备的杆的纵向波动问题,对声子场和相位子场相耦合的控制方程进行数学变换,得出2个标准的波动方程和4种波速。
Power Train The ZF electro-hydraulic shift transmission incorporated has four speeds forward and three reverse, and gear "kick-down" (KD) function with operational easy and efficiency.
变速系采用ZF电液换档前四后三变速箱,具有自动档位切换开关(KD键功能),操纵简便,工作效率高;
The speed of sound in water is about four as great as in air.
声音在水中的速度是空气中的四倍左右
It is clear to all of us that two plus two is four.
二加二等于四对我们大家都很清楚。
He wove four plots together into a novel.
他把四条情节编成一部小说。