291.on faith毫无怀疑地，依赖地
292.faithful to 对忠诚
293.fall into the habit 养成习惯
294.fall short of 没达到，低于
295.familiar with熟悉，了解
296.have a fancy for 喜欢，想要
297.take a fancy to 喜欢
298.by far远，非常
299.far from远远不是
300.far from非但不
301.in favour of赞成
302.be in favour with受宠，受偏爱; out of favour with失宠，不受宠
303.in fashion 时兴，流行
304.after the fashion 依照
305.find fault with 找毛病，对吹毛求疵
306.at fault 有错
307.in ones favour 对有利
308. favourable to 有利的
309.fear for 为担心
310.for fear of 以防，由于怕
311.in fear of 担心
312.feed on sth. 靠吃，用喂养
313.be fed up with 厌烦，腻了
314.feel like 想要
315.fill in填写
316.fill out 填写
317.set the world on fire = set the flames on fire 有突出成就
318.play with fire 干冒险事
319.set sth. on fire 使着火，放火
320.at first sight 乍一看，一见