system units

• 单位制

system units的用法和样例：

例句

1. There are two systems of units in common use in mechanics.
   在力学中通用两种单位制。
2. The unit of impulse, in any system, equals the product of the units of force and time in that system.
   在任一单位制中，冲量的单位等于该单位制中力和时间单位的乘积。