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
331．force...on把……强加给……
332．in the form of以……形式
333．be fortunate in幸运，有好运气
334．free of charge免费
335．be freed from免受，没有……
336．in front of在……前面
in the front of在……前部
337．furnish...with (=supply)向……提供
338．in general (=in most cases, usually)通常
339．catch (or get) a glimpse of瞥见（强调结果）
take a glance (or look) at看……眼（强调动作）
340．be good for对……有好处；对……有作用
be good at擅长于；be good to对……好
341．in good time (=early)早早地（做完，到达等）
342．for good (=for ever)永远地，长期地
343．take...for granted (=assume to be true)把……认为理所当然的
344．be grateful to sb. for sth.因……感谢某人
345．on the ground(s) of (=because of) 由于……
346．fall to the ground（计划，希望等）失败，落空
347．on one's guard (against) 谨防，警惕
(be)on guard站岗
348．guard against (=defend，keep safe) 警惕,防止guard...against警卫……防止
349．guess at猜，估计
350．by guess靠猜