着on fire、罢on strike、出售、偷、公、假，故意、支付，相反、准
Grapes and big water melons from Sinkiang(新疆) are on sale on a large sale.
Do something on the sly (quiet). 秘密地(暗地里，偷偷地)做某事。
I've come here on business. 我是有公事来的。
They went to Bern on a mission. 他们到伯尔尼去执行一项使命。
They have been away on a long trip. 他们出去做一次长途旅行。
I'll go home on leave next month. 下月我将休假回家。
I went on business to Shanghai. I did not take leave. 我是公出去上海的，不是不告而别。 She came to see you on purpose. 她是专程来看你的。
He came here on purpose to discuss it with you. 他到这来是要与你讨论这件事的。
“This lunch is on me.”“这顿午饭我付钱。”“No. let's go Dutch.”“不，还是各付各的。”
On the contrary, it was very easy to understand. 相反，这事儿很容易理解。
P1ease come on time. (on schedule). 请准时来。
The train arrived on schedule. 火车准时到达。
特定时间和“一……就”，左右 on 后动名词
例：Gases expand on heating and contract on cooling. 气体加热时膨胀，冷却时收缩。(特定时间)
On entering the room, he found his friends dancing in high spirits.
一进屋，他就发现他的朋友们在愉快地跳舞。
以及 on the left, right 向左向右，on the stair 在台阶上等。
步行、驴、马、玩笑 on，cab，carriage 用 in
例：On foot 步行; on horse 骑马; on donkey 骑驴。
He rode on, blood flowing from his side. 他骑着马，鲜血从腰部流下来。
The soldier of the Eighth Route Army rode 100 li on a horse a day in order to catch up with his unit. 为赶上部队，那位八路军战士骑马日行百里。
Go on horse back! 骑马去!
You are having me on! 你和我开玩笑呢!
in cab 和 in carriage 不能用 on 或 by cab 或 carriage。
at 山脚、门口在当前，速、温、日落价核心
即在山脚下、在门口、在目前，速度、以……速率、温度、在日落时、在……核心要用at。
例： There is a beautiful lake at the foot of the hill. 山脚下有一个美丽的湖。
At the gate of the house there are many children playing glass ball.
门口有一大群孩子在玩玻璃球。
Who's standing there at the door? 谁站在门口?
I don't need the dictionary at present. 我现在还不需要这本词典。
He is at present in Washington. 他目前正在华盛顿。
The train runs at fifty kilometres an hour. 火车每小时行驶50 公里。
We built the plant at top speed and minimum cost.
我们以最低的投资，最高的速度修建了该工厂。
at home 在国内，在家里 at ten degrees centigrade 在摄氏10 度
at minus ten degrees centigrade 摄氏零下10 度
Water freezes at 0°centigrade. 水在摄氏零度结冰。
Water usually boils at 100°. 水通常在摄氏100 度沸腾。
at zero 在零度 at the rate of 45 miles an hour
at full speed 全速 at a good price 高价 at a low cost 低成本
at a great cost 花了很大代价 at that time 在当时
Evaporation takes place at all temperatures. 蒸发在任何温度下都能发生。
at 1000 RPM (revolution per minute) 每分钟1000 转
at a high speed 高速 at sunset在日落时at daybreak 日出时
The force at the core leading our cause forward is the Chinese Communist Party.
领导我们事业的核心力量是中国共产党。
The atom has a nucleus at its core. 在原子的中心有一个原子核。
At the beginning of this term the teacher in charge of our class was very strict with us. 这学期开始，我们的班主任老师对我们要求非常严格。
以及 At the first session of the First National People's congress of the People's Republic of China. 在中华人民共和国第一次全国人民代表大会第一次会议上.
常用的 at 短语有:
at first 首先，开始时 at least 至少 at all events 无论如何
at home 在家，无拘束 at one stroke 一下子 at a loss 不知怎办
at any rate 不管怎样 at length 详细地 be at high tide 处于高潮期
at our invitation 应我们的邀请 at our request 应我们的请求
at the news 听到这消息 at the risk of 冒……危险
at a great expense 以巨大费用 at a stroke 一举
at intervals of 每隔 at liberty 有权，随意
at the sight of 一见到 at the point of 接近，靠近
at the thought of 一想到 at the speed of 以……速度
at the cost (price) of 以……为代价 at leisure 闲着、失业
at the disposal of 任凭……使用 at stake 在危险中、在成败关头
at bottom 实际上、本质上 at short notice 一得到通知
at seeing us 看到我们 at the happy tidings 听到喜讯
at sixteen 在16岁时 at the present stage 在现阶段
at the weekend 周末 at all times 永远
at 405 Victory Road 在胜利路405号
