fit作形容詞
1.和系動詞連用，表示“適合，恰當”等。
He isn’t fit for his work. 他不適合做這項工作。
The food isn’t fit to eat. 這食物不好吃。
It”s fir that he should say so. 他那樣說是恰當的。
2.和feel或keep等連用，表示精神極好，保持健康等。
Though he is over 70 years old, he feels fit. 盡管他70多歲，但精神頭極好。
I hope you are keeping fit. 我希望你能保持健康。
3.口語中常用作狀語，表示就要，幾乎。
She cried fit to break her heart. 她哭得死去活來
They went on working till they were fit to drop. 他們繼續工作，幾乎要累倒。
fit作名詞
1.前面可以加不定冠詞和形容詞，表示合身，合身的衣服。
Fit is even more important than color. 合身比顏色更重要。
The coat is a good fit. 這件大衣很合身。
2.表示突然爆發或發病等。
When he made a face, the others burst into a fit of laughter. 他做個鬼臉，大家一陣大笑。
He suddenly fell in a fit while he was walking along the street. 當他在街上漫步時，突然昏倒了。
3.口語中常和give或have連用表示大吃一驚，大發脾氣。
That he had passed the exam gave me a fit. 他考試及格了，使我大吃一驚。
When she told her father that news, her father had a fit. 當她告訴她父親那個消息時，她父親大發脾氣。