綿羊是不是可數(shù)名詞?

　　例句：

　　They kept a small flock of sheep.

　　他們養(yǎng)了一小群綿羊。

　　The field had been grazed by sheep.

　　這塊地羊已經(jīng)啃過(guò)了。

　　This wool comes from goats, not sheep.

　　這種羊毛是山羊毛，不是綿羊毛。