281. in the twinkling of an eye 一眨眼,转眼间
282. keep an eye on(=keep a watch on)照看,监视
283. in the eyes of in one’s eyes ( = in the judgment¹ of ) 在某人看来, 在某人眼里
284. on the face of it (=judging by what one can see) 表面看来
285. in the face of 面对着(困难等情况)
286. in one’s face当着某人的面; face to faced面对面; face up to 大胆面向
287. fail in (=be unsuccessful in) 失败
288. in good faith(=honestly, sincerely) 真诚地
289. keep faith with 对…守信用
290. lose faith in 对…失去信心
291. on faith 毫无怀疑地, 依赖地
292. faithful to (=loyal to) 对…忠诚
293. fall into the habit (of) 养成…习惯
294. fall short of (=fail to reach a desired result, standard, etc.) 没达到, 低于
295. familiar with 熟悉,了解
296. have a fancy for ( =like sth. without the help of reason) (没有道理地)喜欢, 想要
297. take a fancy to (=become fond of) 喜欢
298. by far 远, 非常 (与比较级或最高级连用)
299. far from 远远不是
300. far from 非但不…(而且)
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) favourable² 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