beef是可數(shù)名詞嗎?

　　例句：

　　Kenya's beef comes from the zebu cattle.

　　肯尼亞的牛肉是瘤牛肉。

　　They serve the most delicious roast beef.

　　他們做最美味的烤牛肉。

　　The smell of roast beef permeated the air.

　　烤牛肉的氣味彌漫在空氣中。