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……