囚犯受到严密监视。用英语怎么说？

囚犯受到严密监视。

The prisoners were closely guarded.

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

prisoners

n. 囚徒( prisoner的名词复数 )，俘虏，被夺去自由的人[动物]等；

例句
The regulations were relaxed and the prisoners could get out and about a bit.
规定有所放宽，犯人可以出去短暂放风。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

closely

adv. 接近地，紧密地，严密地，亲近地；

例句
...a closely contested regional flower show.
各方争奇斗艳、难分高下的地区花卉展

guarded

adj. 谨慎的，有保留的；v. 保护，控制( guard的过去式和过去分词 )；

例句
The boy gave him a guarded look...
那个男孩充满戒心地瞧了他一眼。