301. in fashion(=stylish, most modern)時興,流行
302. after the fashion (of) 依照…
303. find fault with(=complain about; criticize)找毛病，對…吹毛求疵
304. at fault (=in the wrong, blamable)有錯
305. in favour of 贊成
306. be in favour with 受寵, 受偏愛;
out of favour with 失寵, 不受寵
307. in one’s favour(=to one’s advantage)對.有利
308. (be) favourable to(=advantageous)有利的
309. fear for (=be afraid for the safety of sb. or sth.) 為…擔心
310. for fear of (=in case of; because of anxiety about) 以防, 由於怕
311. in fear of (=afraid for the safety of) 擔心
312. feed (sb.) on sth. 靠吃…, 用…餵養313. be fed up with(=be unhappy, tired about sth. dull) 厭煩, 膩了
314. feel like (=have a desire for) 想要
315. fill in 填寫
316. fill out ( =fill in )填寫
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)乾冒險事
319. set sth. on fire(=set fire to sth.)使..著火,放火
320. at first sight(=when first seen)乍一看,一見
321. for the first time 第一次 (作狀語)
322. in the first place 首先, 第一
323. fit into 剛好放入
324. fit in with ( = suit , fall into agreement) 合適, 相配, 一致
325. (be) fit for (=right and suitable for) 適合
326. focus on (=concentrate on) 集中在…上
focus sth. on 把…集中在…上
327. be fond of 喜歡
328. (be) in force 有效 , 實施