1.act as 担当…， 起…的作用

Special forces act as death squads hunting down insurgent leaders.
特种部队在一直充当追捕叛军首领的敢死队角色。

As for censorship, chief editors act as the ultimate gatekeepers.
为了审查，主编就充当了终极门卫的角色。
2.set free 释放；放走

He has made them set free captured mahdi army leaders.
马利基让他们释放了被捕的迈赫迪军领导人。

After that, he must be set free for a short time.
以后必须暂时释放他。

3.carry out 执行；进行

They say he used a military-style assault rifle to carry out the shooting spree.
警方表示，他使用一支军用突击步枪进行了这次疯狂枪杀。

They have their own laboratory where they carry out about 30 water tests an hour.
他们自己拥有的实验室，在实验室里每个小时可以进行30次水质测试。

4.jolt into 变成

The economy's jolt into recession in 2009, when it shrank by almost 8%, forced a rethink.
2009年俄罗斯出现经济衰退的动荡，当它下跌到近8%时，人们被迫进行反思。

Money permitting, maybe a spate of joblessness would jolt me into taking more initiative.
如果财力允许，或许失业一阵子会迫使我变得更加主动。