(1) On the air：在广播中
The Prime Minister’s National Day speech was broadcast live and will be on the air again.
(2) On balance：权衡轻重之后
Our national football feam sometimes won but sometimes lost. On balance, it has had a quite good track record.
(3) On the dole：接受福利金
In the West, unemployed workers can still survive if they are on the dole.
(4) On an even keel：平稳的
The grocery business has experienced a tough period, but it is back on an even keel.
(5) On the loose：不受拘束的
According to some newspaper reports, a big tiger is on the loose in an outlying island.
(6) On the make：热衷于追求名利
Among your friends, do you have some continually on the make?
(7) On the mend：病情在好转件
When I saw Mike last time, he was quite ill, but he is now said to be on the mend.
(8) On the move ：在活动中
A good friend of mine has been on the move in and out of the country, trying to find business to do.
(9) On a par with：……和……平等
The flowers in that garden are pretty, but I am not sure if they are on a par with yours.
(10) On the quiet：秘密地
Some foreign students have been making money on the quiet during school holidays.
(11) On the rocks：遭受失败
His ill-fated attempt has landed itself on the rocks.
(12) on the run：在逃跑中
One kidnapper has been arrested, but others are still on the run.
(13) On a shoestring：小本经营地
Xiao Lei ran his business on a shoestring before it was expanded.
(14) On the side：作为兼职
Some low-income people have to take up a second job on the side.
(15) On the sly：秘密地;偷偷地
Smoking was prohibited in school, but some students did it on the sly or in the lavatory.
(16) On the spot：当场;立即
When an adult shoplifter is caught on the spot, he or she will be sent to prison.
(17) On tenterhooks：提心吊胆
Those waiting for the outcome of university admission are on tenterhooks beyond their control.
(18) On the rack：极度焦虑不安
When the doctor did not say anything after seeing the patient, the patiant felt somewhat on the rack.
(19) On tap：随时可得到的
The director has a wide circle of friends who are on tap when needed.
(20) On the cards ：有可能重现的
Unconfirmed news has it that a new university could be on the cards.
(21) On edge：紧张;着急;
When the small boy could not see his mother in the crowd, he was on edge and cried.
(22) On call：待命
The company car is always on call to take the Chief Executive Officer to meetings.
(1) In the air：尚未确定的
Some neighbouring governments’ concrete plans to alleviate their economic problems are still in the air.
(2) In clover：(常和 “live”连用)生活舒适
Those living in clover will not be able to understand the misery of the poor.
(3) In deep water：深深陷入困境
You had better get away from that business or you will be in deep water with no one to pull you out.
(4) In low spirits：士气低沉的
What’s wrong with you ? You looked fine a moment ago. Why are you now in low spirits?
(5) In a fix：面临困境
Some newly-weds are in a fix now; when can they get their HDB flats and move in ?
(6) In a flutter：处在紧张状态中
The news about the dignitary’s visit put the staff in a flutter.
(7) In full swing：如火如荼地
The celebration for welcoming the victorious national team is already in full swing.
(8) In the know：知道详情的
The manager has resigned. For further information, please see the secretary, who is in the know.
(9) In limbo：处于不确定的状态中
The decision on the oversea project is in limbo, due to some indeterminate factors.
(10) In a flash：瞬息间
I don’t know what happened to Grace, who went out and retuned in a flash.
(11) In the limelight：众人注意的焦点
Once a person becomes famous, he will be in the limelight. all the time with very litte private time.
(12) In a nutshell：简而言之
I have a lot to say about his latest book, but to put it in a nutshell, it is a good work.
(13) In the offing：即将到来
According to a newspaer report, a minor cabinet reshuffle is in the offing.
(14) In the pipeline：在准备中
The TV magazine indicates that some new TV serials are in the pipeline.
(15) In the open：公开的
The hearsay about a minister’s resignation has now become a fact; everything is now in the open.
(16) In the same boat：面临同样的不幸处境
If a company cannot survive, many others will be in the same bboat, and working people will be in for a hard life.
(17) In step with：和……符合
Is it possible to expect the opinion of every member to be in step with that of the party leaders?
(18) In store for：即将发生;即将到来
For every capable person, there is a promising future in store for him.
(19) In the swim：通晓时务
If you are to keep your information up to date, please see Jimmy, who is always in the swim.
(20) In a tight squeeze：(财务等)紧缩
When in a tight squeeze, a company has to resort to the bank for assistance.
1. At bay：(经常和keep或hold连用)使……不能接近
One of the gangsters kept the police at bay until the rest escaped.
2. At bottom：实际上
Judy said she was not jealous of her friends’ success, but at bottom, she was.
3. At close quarters：逼近地
The two rivals grappled at close quarters.
4. At cross purposes：互相误解
I think we are at cross purposes. When I said “J.C.”, I meant “Jason Chen”, not “John Chen”.
5. At daggers drawn：势不两立
Dan and Bob have been at daggers drawn for years. There is no evidence that they will make up.
6. At every turn：处处
When you go downtown, you will see shops, big and small, at every turn.
7. At one fell swoop：一举
Which country can invade another country and conquer it at one fell swoop?
8. At issue：在讨论中的
The question asked was not relevant to the matter at issue .
9. At large：一般的;逍遥法外的。
a. The people at large support the government’s various policies.
b. Some illegal immigrants were caught, but some others are still at large.
10. At length：详细地
Time did not allow the speaker to talk about the financial turmoil at length.
11. At loggerheads with……：经常和……争吵
Mr and Mrs Thang are often at loggerheads with each other. Why can’t they get along well?
12. At a loss for words：不知说什么好
The news came so surprisingly that she was at a loss for words.
13. At a low ebb：处于低潮
Henry’s mood seems to be at a low ebb now; let’s cheer him up a bit.
14. At a price：付高代价
Some people became successful at a price; their health and family life were adversely affected.
15. At random：随意地
One may choose things at random, but not the prospective life partner.
16. At the ready：处在准备状态中
At the news conference, news reporters gathered around, pens and notebooks at the ready.
17. At sea：茫然
Those not interested in politics will be at sea when people discuss political issues.
18. At a stretch：连续地
In order to earn money, some workers do overtime works for a few days at a stretch.
19. At will：任意地
In a society like ours, one has to be law-abiding and not to do things at will.
20. At one’s wits end：不知所措
Chased by the enemy to an abyss, the man could not advance any more, nor could he retreat; he was at his wits end.
21. At heart：在内心里;本质上
a. A good leader often has the people’s interests at heart.
b. Though Xiao Gan works in a city, he is a country boy at heart.
22. At sixes and sevens：乱七八糟
When the maid returned to work after three days’ leave, she found all the rooms at sixes and sevens.