potato是不是可數名詞?

　　例句

　　1、The potato cakes should be crisp outside and meltingly soft inside.

　　土豆餅應該外面酥脆,里面嫩軟.

　　2、Now experts are extolling the virtues of the humble potato.

　　現在專家們都在贊美其貌不揚的馬鈴薯的種種好處。

　　3、Left-handers have trouble using can-openers, scissors, and potato peelers.

　　左撇子在使用開罐刀、剪刀和土豆削皮器時會有困難。