400. on occasion(s) 有时,间或
401. on one's guard 警惕,提防
402. on one's own 独立,独自
403. on purpose 故意地
404. on sale 出售,廉价出售
405. on schedule 按时间表,准时
406. on second thoughts 经重新考虑
407. on the contrary 正相反
408. on the grounds of 根据,以...为由
409. on the other hand 另一方面
410. on the point of 即将...的时刻
411. on the road 在旅途中
412. on the side 作为兼职/副 业
413. on the spot 在场;马上
414. on the whole 总的来说,大体上
415. on time 准时
416. on(an/the) average 平均,通常
417. once (and) for all 一劳永逸地
418. once again 再一次
419. once in a while 偶尔
420. once more 再一次
421. once upon a time 从前
422. one another 相互
423. one's cup of tea喜欢的人/物
424. open to不限制,开放的
425. opposite to在对面
426. or else 否则,要不然
427. or so 大约,左右
428. other than 非;除了
429. out of breath 喘不过气来
430. out of control 失去控制
431. out of date 过时的
432. out of doors 在户外
433. out of order 出故障的
434. out of place 不适当的
435. out of practice 久不练习,荒疏
436. out of sight 看不见,在视野外
437. out of the question 毫无可能的
438. out of touch 不联系,不接触
439. out of 从...中;由于;缺乏
440. over and over (again) 一再地,再三地
441. parallel to与...平等,类似
442. particular about挑剔,讲究
443. patient with有耐心
444. peculiar to独特的,独有的
445. pick up捡
446. play by ear见机行事
447. popular with受...喜爱,爱戴
448. prior to 在...之前
449. pull one's leg拿某人开玩笑put someone on
450. put someone up给某人提供住宿
451. put up with忍受
452. quite a few 相当多,不少
453. rain cats and dogs瓢泼大雨
454. rather than 不是...(而是)
455. reach agreement 达成协议
456. reach an agreement达成一致
457. regardless of 不顾,不惜
458. relative to与...有关
459. remove from 从…除去
460. representative of代表...的
461. resign one's post 辞职
462. responsible for负责,是...原因
463. result from 由于
464. rich in富于
465. right away 立即,马上
466. ring sb. up 打电话给…
467. rule out 排除…的可能性
468. run out of用完
469. rush hours上下班高峰
470. see: see to it that - make sure that确保
471. sensible of觉查到
472. sensitive to对...敏感
473. set another date改期 make on saturday / lock it
474. set one's mind on doing 决定be determined to / have one's mind set on / bent on
475. short of缺少
476. show off卖弄
477. sick of厌恶,厌倦
478. side by side 肩并肩,一起
479. similar to相似
480. skilled at /in善于
481. slip one's mind 忘记
482. so far 迄今为止
483. somewhere around 大约
484. sooner or later 迟早,早晚
485. sore throat / foot
嗓子哑/腿酸
486. stay up late 熬夜
487. step by step 逐步地
488. subject to受制于,易于
489. such as 例如,诸如
490. sufficient for足够的
491. suitable for/to适合于
492. superior to优于,级别高于
493. sure of /about对...有信心,确信
494. suspicious of怀疑
495. take a leave请假
496. take a seat / be seated
497. take one's place 取代
498. take one's time慢慢来
499. take sth. seriously 认真对待
500. take up占据