beating是動名詞還是現在分詞？

adj. 責打, 笞打, 打敗, 敗北

n. 攪打, 敲, 失敗

例句:

He's alive his heart is still beating.

他還活著－－心臟還在跳。

We heard the drums beating.

我們聽到了敲鼓的聲音。

Somebody was beating at the door.

有人不停地敲門。