The stair treads were covered with rubber to prevent slipping.是什么意思？

The stair treads were covered with rubber to prevent slipping.

楼梯踏板上覆盖着橡胶以防滑.

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。

stair

n. 楼梯，（楼梯的）一级；

例句
Clutch stair armrest, move carefully step by step.
抓紧楼梯扶手, 一步步谨慎地移动.

treads

v. 踩，踏( tread的第三人称单数 )，踩成，踏出，步行于；

例句
He walked up the stairs. The treads were covered with a kind of rubber and very quiet.
他走上楼梯。梯面上铺了一种橡胶，因此没有什么声响。

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。

covered

adj. 大量的，有遮盖物的，（尤指）有顶的；v. 覆盖( cover的过去式和过去分词)，掩护，包括；

例句
I covered the scroll in sealing wax, and affixed a red ribbon.
我用封蜡将卷轴封好，并系上一根红丝带。

with

prep. 和，跟，随着，关于，和…一致；

例句
A waiter entered with a tray...
侍者端着托盘进来了。

rubber

n. 橡胶，橡皮，决胜局，避孕套；adj. 橡胶制成的；vt. 涂橡胶于，用橡胶制造；vi. 扭转脖子看，好奇地引颈而望；

例句
Seven people were wounded when soldiers fired rubber bullets to disperse crowds...
士兵发射橡皮子弹驱散人群时有7个人受了伤。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

prevent

vt. 预防，阻碍，阻止，[宗教]引领；vi. 阻挠，阻止；

例句
...an abortive attempt to prevent the current President from taking office.
企图阻止现任总统连任的失败尝试

slipping

adj. <美俚>渐渐松驰的，渐渐不行了的，渐渐变懒的；v. 滑( slip的现在分词 )，滑脱，下降，（健康状况等）变差；

例句
And a number of African countries, too, are slipping through the net...
并且一些非洲国家也被漏掉了。