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 out of date 过时的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

474. set one's mind on doing 决定

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