（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.