| 301．in fashion (=stylish，most modern) 时兴，流行
302．after the fashion (of)依照……
303．find fault with (=complain about；criticize)找毛病，对……吹毛求疵
304．at fault (=in the wrong, blamable)有错
305．in favour of赞成
306．be in favour with受宠，受偏爱；
out of favour with失宠，不受宠
307．in one's favour (=to one's advantage)对……有利
308．(be) favourable to (=advantageous)有利的
309．fear for (=be afraid for the safety of sb. or sth.)为……担心
310．for fear of (=in case of; because of anxiety about)以防，由于怕
311．in fear of (=afraid for the safety of)担心
312．feed (sb.) on sth. 靠吃……，用……喂养
313．be fed up with (=be unhappy, tired about sth. dull)厌烦，腻了
314．feel like (=have a desire for)想要
315．fill in填写
316．fill out (=fill in)填写
317．set the world on fire = set the flames on fire (=do sth. remarkable)有突出成就
318．play with fire (=take great risks)干冒险事
319．set sth. on fire (=set fire to sth.)使……着火，放火
320．at first sight (=when first seen)乍一看，一见
321．for the first time第一次（作状语）
322．in the first place首先，第一
323．fit into刚好放入
324．fit in with (=suit, fall into agreement)合适，相配，一致
325．(be) fit for (=right and suitable for)适合
326．focus on (=concentrate on)集中在……上
focus sth. on把……集中在……上
327．be fond of喜欢
328．(be) in force有效，实施
329．go into force开始生效
330．by force靠武力，强行