The bell is knelling.是什么意思？

The bell is knelling.

丧钟已经敲响.

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。

bell

n. 钟，铃，钟声，铃声，钟状物，[建]圆屋顶；vt. 敲钟，系铃于，给…装上铃，使成铃状，把…放在钟形罩内；vi. 使象钟状地张开，鸣钟；

例句
I had just enough time to finish eating before the bell rang and I was off to my first class...
我刚吃完饭铃声就响了，于是我赶去上第一堂课。

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

knelling

v. 丧钟声( knell的现在分词 )，某事物结束的象征；

例句
The old cat whose child has just been dead is knelling all the time.
那只刚刚失去孩子的老猫不停地发出悲哀的声音.