墓碑跟在后面，滑下来倒在我身上；

The gravestone follows, slides down over me;

youdao

我不希望梯子滑下来，所以我要求，摩擦力必须小于，或者等于，摩擦力的可能最大值。

Now, I don't want this ladder to slide, so now I have a requirement that the frictional force must be less or equal to the maximum frictional force possible.

youdao

我从楼梯上滑下来，把踝骨跌断了。

I slipped on the stairs and broke my ankle.

youdao