Scaffolds and ladders should be checked and maintained constantly.是什么意思？

Scaffolds and ladders should be checked and maintained constantly.

脚手架和楼梯须经常检查和保养.

scaffolds

n. 脚手架( scaffold的名词复数 )，<史>断头台；

例句
The special architecture and biodegradation characters of scaffolds could influence the vascularization.
材料的结构和降解特性影响血管化.

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

ladders

n. 梯子( ladder的名词复数 )，阶梯，途径，（紧身裤袜或长筒袜的）滑丝；

例句
Some did manage to claw their way up iron ladders to the safety of the upper deck.
的确有人设法抓住铁梯爬上了顶层甲板，脱离了危险。

should

应该，将会，可能，本应；

例句
The older child should be able to prepare a simple meal...
那个年纪稍大的孩子应当会做一顿简单的饭菜。

be

v. 是，有，存在，做，成为，发生；aux. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质；

例句
The older child should be able to prepare a simple meal...
那个年纪稍大的孩子应当会做一顿简单的饭菜。

checked

adj. 方格图案的，受阻的，封闭的；v. 检查，核对(check的过去式和过去分词)；

例句
The assistant took the book and checked the price on the back cover...
店员拿起书，核对了一下封底的定价。

maintained

v. 保持( maintain的过去式和过去分词 )，保养，坚持，保卫；

例句
He maintained an ambivalent attitude to the Church throughout his long life.
在他漫长的一生中，他对基督教信仰始终是一种摇摆不定的态度。

constantly

adv. 不断地，时常地，始终，一直；

例句
Her dedication constantly astonishes me.
她的奉献精神总是让我震惊。