一.interest當(dāng)利息用時 ,為不可數(shù) 如：
I borrowed the money at 5% interest.
二.interest當(dāng)興趣用時既有可數(shù)名詞又是不可數(shù)名詞,
例如下面的幾種用法：
1.興趣;關(guān)注;愛好
I developed an interest in the machine.
我對這機(jī)器發(fā)生了興趣.
I have lost my interest in chemistry.
我對化學(xué)已不感興趣.
2.趣味性(+to)
Local color added interest to the novel.
地方色彩增加了這部小說的吸引力.
3.感興趣的事物或人（這是就可數(shù)）
His two great interests in life are music and painting.
三.股份,股權(quán)(+in)]
He has an interest in the company.
他在這家公司擁有股份
四.利潤,福利,利益,好處
He always puts the interests of the people before his own.
他總是把人民的利益置于個人利益之上