on one's head . easily易如反掌地

When asked if he could lift the big stone，the boy said he could do it on his head．当有人问那男孩能否举得起那块大石头时，他说这不费吹灰之力。

on one's high horse . being very proud and scornful 趾高气扬；自高自大

I don't like him：he's always on his high horse， thinking he can order everyone else about．不喜欢他，他总是趾高气扬的，以为什么人都得听他的。

Martha was chairman of the picnic committee， and at the picnic she was on her high horse， telling everyone what to do．玛莎是野餐会的主席，在野餐时她盛气凌人地指挥每个人怎么做。

on one's high horse . in a bad temper发脾气．

The girl was on her high horse because she found her boyfriend insincere．姑娘发现她的男友不诚实，非常生气。

on one's honor . trusted信任

The students were not supervised during the examination．They were on their honor not to cheat．学生考试时没人监考。老师相信他们不会作弊。

on one's knees .  pleading； begging very hard求饶

The children were on their knees for hours before their parents agreed to their camping plans．孩子们求了几个小时家长才同意让他们去野营。

on one's knees .  in a very weak condition；near failure处于困境；濒临失败

The company was on its knees owing to a decrease in its sales．由于销售额下降，公司陷入了困境。

on one's own . with no help from others； independent自立

You are allowed to drive a car on your own．允许你独自开车。

I'm all on my own today．今天只是我一个人。

Why are you sitting all on your own? 你为什么独自一个人坐在那里?

I don't need your advice， thanks． I can do it on my own．谢谢，我不需要你的忠告，我自己能做。

I can tackle problems on my own．我能独立解决问题。

on one's own account .  for oneself为自己

After they had picked out the school gift， some staff members did some shopping on their own account．挑选出了学校礼品后，一些员工为自己购货去了。

He bought the watch on his own account，not for his brother．这表不是给他兄弟买的，而是为他自己买的。

on one's own account . independently独立地

It is too dangerous； I dare not do it on my own account．这太危险了，我不敢独自一人担这个风险。

 on one's toes .  alert；ready to act机警；准备去做

A good ball player is always on his toes．好的球员总是很机警的。

on one's way .on one's way to . on the way to在（赴…的）途中

I'll buy some apples on my way home．在回家的路上我要买些苹果。

on order . requested but not yet supplied 订购中

The shop assistant told the customer that they didn't have this type of shoes in stock then， and that they were on order．售货员告诉顾客他们店现在这种鞋已没货了，正在订购中。

When do you think you can ship the goods on order? 你认为何时能运走所订的货物?

on paper . judging by appearance表面上看

The football team look good on paper，but they have lost many games．这支足球队表面上看来挺不错，但他们已经输了许多场球。

on paper . in written words以书面形式

We must get the agreement down on paper．我们必须将此协议形成文字。

on paper .  in theory理论上；从文字上看

The idea sounds good on paper，but I'm not sure whether it will really work．这个主意从字面上看是很好的，但我不敢肯定它是否真正能行得通。

The applicant looks good on paper．从书面材料看，这个申请人的情况很不错。

on pins and needles . worried焦虑；坐立不安

Jane was very late getting home from school， and her mother was on pins and needles．简放学很晚才回家，她妈妈焦急不安。

The wounded soldier was on pins and needles， wanting to know the fate of his comrades．那位伤员因急于想知道战友们的情况而焦虑不安。

on principle . as a moral matter按道理；原则上

He drinks a cup of hot milk every night on principle．他每晚照例喝一杯热牛奶。

I dislike going out for meals in restaurants on principle； why should you pay so much money for food that you could prepare yourself? 我就是不喜欢去外面餐馆吃饭，干吗要花那么多钱去买那些自己能做的食物呢?

on purpose . intentionally故意地

Jimmy hit his little brother in the eye， but he didn't do it on purpose．杰米打了他弟弟的眼睛，但他不是故意的。

She did not forget her coat； she left it in the locker on purpose．她并未忘记要带外衣，她是故意放在锁柜里的。

She broke the dish on purpose just to show her anger．她故意打破那个盘子以发泄她的愤怒。

on record .  written down in a record记录在案的

We don't know when the famous writer was born，but the date of his death was on record．我们不知道这位名作家何时出生，但他的去世日期是有记录的。

It is on record that this summer was the hottest in fifty years．据记载，今年夏天是五十年来最热的。

on record .  known to have said or done a certain thing人所共知的

That congressman is on record as an enemy of waste in government．那位国会议员以反对政府浪费而著名。

on sale . selling for a special low price削价出售

These shoes are very cheap， as they are on sale．这些鞋子非常便宜，正在削价出售。

The bookstore is to close down，and many books are on sale as waste paper．书店要关闭，所以许多书象废纸一样在廉价出售。