19. in one/same direction同一方向one-sided 片面的 one-way 单方面one by one 一个接一个

18. I have been here once.(一次) I once lived here.(曾经)　 once again 再来一次

at once 马上, 同时 I can't do two things at once.　　　 once more 再一次 (once again)

once a day 每天一次　　　 once in a while 偶尔

17. have nothing on 没穿…　 go straight on/ahead　 笔直朝前　　 on the table

There is a new film on on channel 8. 上演 ,　

play a joke on sb 开…一个玩笑　　 in time 及时　　　 on time 准时　　

be based on　　　 on business 因公 on holiday 度假　 on the way to 在途中

on foot　 on tiptoe 悄悄地　　 on hire　

on purpose = by design　　 正好相反　　　 on the other hand 另一方面　

on doing 一…就…　　 On getting off the plane, I recognized him.

16. omit 省略　 You may omit the second paragraph from the article.

15. an official letter　 公函　 　　news from an official source　 官方消息

14. offer to do = make an offer to do 主动提出做…　　　 offer sb sth = offer sth to sb　　 提供　

　　 I offered him ￥100 for his bike. 我出100元买他的车。

13. offend sb　 冒犯　　 be offended with sb　 生…的气　　 be offended at sth

12. see sb off　　 turn/switch off　　 take off 取消，脱衣，起飞，离开　　 be well off 富有

pay off 还清　　 be off duty 不上班　　 off the point 不在要点

May Day is only a week off.　 五一只有一星期了.

11. in the east of　 be born of 出生于　 be afraid of　　 be made of (材料不可见)　 be full of

of the same opinion/age 　think of 记起(think about 考虑)　 dream of 梦见　 learn of 记牢

be made up of 由…组成　　 in memory of 纪念　　　 in search of 寻找　　 cure sb of

get rid of 除去　 inform sb of 通知　 remember of 记起…　 suspect sb of 怀疑　 rob sb of　　　　 out of stock　 　all of a sudden 突然 　

10. odd　 古怪的　 oddly enough = strangely enough 说也奇怪　　 odds and ends 零碎小东西