281. in the twinkling of an eye 一眨眼,转眼间
282. keep an eye on照看,监视
283. in the eyes of in one’s eyes 在某人看来, 在某人眼里
284. on the face of it 表面看来
285. in the face of 面对着
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 失败
288. in good faith 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 对…忠诚
293. fall into the habit 养成…习惯
294. fall short of 没达到, 低于
295. familiar with 熟悉,了解
296. have a fancy for 喜欢, 想要
297. take a fancy to 喜欢
298. by far 远, 非常
299. far from 远远不是
300. far from 非但不…
301 in fashion时兴,流行
302. after the fashion 依照…
303. find fault with找毛病，对…吹毛求疵
304. at fault 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对.有利
308. favourable to有利的
309. fear for 为…担心
310. for fear of 以防, 由于怕
311. in fear of 担心
312. feed on sth. 靠吃…, 用…喂养
313. be fed up with 厌烦, 腻了
314. feel like 想要
315. fill in 填写
316. fill out 填写
317. set the world on fire=set the flames on fire有突出成就
318. play with fire 干冒险事
319. set sth. on fire使..着火,放火
320. at first sight乍一看,一见