The motion of a body when acted upon by a constant force was considered in detail in chapter 4 and 5 . 在第四、五两章详细讨论了物体在恒力作用下的运动。
If a particle is moving it keeps on going in the same direction unless forces act upon it . 如果一个粒子正在运动，它将沿着同一方向继续运动下去，除非有力作用其上。
A portrait over the chimneypiece, painted by the fashionable artist of the day, acts upon him like a charm . 壁炉架上有一幅当时时兴的画家画的肖像，简直使他着了魔。
Earthworms burrow and bring rock particles to the surface to be acted upon by heat, cold, air and water . 蚯蚓挖洞而把岩石颗粒带到地表，使它们经受热，冷、空气和水的作用。
When a body is at rest, or in motion with constant velocity, the external force acting upon it are in equilibrium . 当物体处于静止或作匀速运动时，作用在其上的外力是平衡的。
When a charged particle is so situated that an electric force acts upon it, we say that it is in an electric field . 当一个带电粒子处在有电力作用于它的状态下时，我们就说它处于电场中。
It was not wise to act upon an impulsive instruction without making sure that the reflective nixon had had a crack at it . 在没有弄清楚尼克松是否经过仔细考虑，就去执行他的一时冲动的指示，那是不明智的。
To obtain and act upon the opinion ( s ) of the judges 获得和执行与副审们之意见。
We should have some principles to act upon 我们应该有一些原则，以便遵循行事。
A single sql statement can act upon multiple rows 一条sql语句可以作用于多行。
