介词用法详解(8)

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。 On reaching the city he called up Lao Yang. 一到城里他就给老杨打了一个电话。

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

I'll write to him on hearing from you. 我接到你的来信就给他写信。(一……就)

这本词典。

He is at present in Washington. 他目前正在华盛顿。

以及 on the left, right 向左向右，on the stair 在台阶上等。

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.

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。

at minus ten degrees centigrade 摄氏零下10 度

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。

Water usually boils at 100°. 水通常在摄氏100 度沸

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 full speed 全速 腾。

at zero 在零度

at the rate of 45 miles an hour

Water freezes at 0°centigrade. 水在摄氏零度结冰。 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 山脚、门口在当前，速、温、日落价核心

at a good price 高价 at a low cost 低成本

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：At the foot of the mountain, there are thirty of our comrades.

在山脚下，有我们30 个同志。

There is a beautiful lake at the foot of the hill. 山脚下有一个美丽的湖。

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