Bill was a senior police officer who joined the force back in1982.

比尔是一位高级警官，他早在1982年就加入了警察队伍。

If an arm is stretched forward under water resistance is increased and a reaction force back ward is developed both of which would contribute to negative acceleration.

如果手臂在水中是向前伸展则阻力会随之增加而向后方的反作用力也会出现，二者都会产生负加速度。

Hand at her mouth she stared while Melanie packed a fresh towel against his shoulder pressing it hard as though she could force back the blood into his body. but the towel reddened as though by magic.

她捂着嘴注视着里面，看见媚兰又把一条毛巾放在他的肩上，使劲压，好像能把流出来的血压回去，但是这条毛巾马上又红了，像变戏法一样。

The War Department sent General George Crook to punish the Indians and force them back to their reservation.

VOA : special.2010.04.08

If the Union force attacked before Stonewall Jackson got into position, Lee could not possibly hold it back.

VOA : special.2009.10.15

Whenever there is a force, it can be traced back to a tangible material cause, which is all the time a force of contact, with the exception of gravity.

如果有作用力,那它一定能找到一个明确的实体施力物体,也就是无论何时物体受的都是接触力,引力除外

基础物理课程节选 : 耶鲁公开课

That puts great force on the back of the foot.

VOA : special.2010.02.03

Synthetic vision systems were created by NASA and the U.S. Air Force back in the late 1970s to improve cockpit situational awareness, especially when operating in reduced visibility at low altitudes.

FORBES: Flying Blind No Longer

"If someone is prepared to take the life of a police officer they are entitled to expect severe force back at them and it is unfortunate one of the attackers was not hit, " he added.

BBC: The street where the device was found on Saturday

We examined the case of a hypothetical senior retiring at the end of 2009 at age 66, who had the freedom to choose personal accounts when he entered the work force back in 1965 at the age of 21.

FORBES: Social Security Personal Accounts Are A Path To Prosperity