介词用法讲解

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 minimun 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. 水在镊氏零度结冰。
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 tempertures. 蒸发在任何温度下都能发生。
at 1000RPM (revolution per minute) 每分钟1000 转
at a high speed 高速
The soldiers launched an attack upon the enemy at sunset. 战士们在日落时对敌人发起了攻击。
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**。
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
工具、同、和、随with，具有，独立、就、原因：
例：We write with ballpens. 我们用油笔写字。(工具)
但He write in blue ink. 他用蓝水笔写字(墨水用in 不用with)
Theory must go hand in hand with practice. 理论必须同实践相结合。(同)
He is talking with friends. 他正同朋友们谈话。〔同)
I'd like to have a dinner with a friend. 我喜欢同朋友共同进餐。
We must co-operate closely with them. 我们必须同他们紧密合作。(同)
We, as human beings are going to leave, but friendship has taken roots among us and our hearts are linked withyours. 我们虽然就要走了，但是友谊却在我们之间扎了根，我们的心和你们的心是紧紧相连的。(和或同〕
A cadre must become one with the masses.干部必须和群众打成一片。
I'm with you. 我同意你。
An atom is so small that we can't see it with a microscope. 原子太小，即使用显微镜也看不见它。(工具)
In the past I had to part with my wife. 旧社会我不得不和妻子离别。(和)
The socialist revolution is deepening with each passing day. 社会主义革命日益深入。(随着)
They sail with the wind. 他们顺风航行。(随着)
With the change of the economic foundation, the superstructure has to be transformed too. 随着经济基础的改变，上层建筑也必须改变。(随着)
With the battlle of Waterloo, Napoleon's rule in Europe was ended. 滑铁卢一战，拿破仑对欧洲的统治就完蛋了。
The modern electron tube. 随着电子管的发明而诞生了现代电子工业．
She is with child. = She is in a very interesting condition. = in a family way, = She is pregnant (inpregnancy). 她怀孕了。(有)
但She is with a child．意为:"她领着一个孩子。"
China is a very large country with a long history. 中国是一个历史悠久的大国。(具有)
China is a country with a population of ten billion people. 中国是一个有10 亿人口的国家。（具有）
What is the matter with you? 怎么回事?(就，关于)
How is it with you? 你怎么啦？(就，关于)
Everything was going well with them. 他们一切都进行得很顺利。(就……)
It is a very intense flash with a lot of power packed into it. 由于聚集了大量的能，所以闪光非常强烈。（独立结构）
注；即分词独立主格结构用with。
With a new welding technique introduced, the use of stainless steel was no longer limited to making small thingsonly. 由于新的焊接技术的引进，不锈钢的使用就不仅仅局限在微小的物件上了。(独立结构)
With all its beams advancing in step with each other the laser possessed very particular properties which noordinary light ever has. 由于激光的光束同步，所以它具有普通光所没有的特殊性质。(独立结构)
Without the temperature or pressure changed matter can never change from one state into another. 没有温度或压力的变化，物质永远不能以一种状态变到另一种状态。(独立结构)