介词“in”的用法
“in”是英语中最为活跃的介词之一，所以它给我们的学习带了很大的挑战。细分下来，它有如下用法
年、月、年月、季节、周
即在"来年"，在"某月"，在"某年某月" (但在某年某月某
日则用on)，在四季，在第几周等都要用in。
例；in 1986 在1986年
in 1927 在1927年
in April 在四月
in March 在三月
in December 1986 1986年12月
in July l983 1983年7月
in spring 在春季 in summer 在夏季
in autumn 在秋季 in winter 在冬季
in the fist week of this semester 这学期的第一周
in the third week 在第三周
阳光、灯、影、衣、冒 in，
即在阳光下，在灯下，在树阴下，穿衣、着装、冒雨等都要用in。
例：Don't read in dim light. 切勿在暗淡的灯光下看书。
They are reviewing their lessons in the bright light. 他们在明亮的灯光下复习功课。
They are sitting in the shade of a tree. 他们坐在树阴下乘凉。
a prisoner in irons 带着镣铐的囚犯
He went in the rain to meet me at the station. 他冒雨到车站去接我。
The poor dressed (clothed) in rags in old society. 旧社会穷人们衣衫褴褛．
以及：in the bright sunlight 在明亮的阳光下
a merchant in disguise 乔装的商人
the woman in white (black, red, yellow) 穿着白(黑、红、黄)色衣服的妇女
in uniform 穿着制服
in mourning 穿着丧服
in brown shoes 穿着棕色鞋
in his shirt sleeves 穿着衬衫
将来时态in...以后
例: They will come back in 10 days. 他们将10天以后回来。
I'll come round in a day or two. 我一两天就回来。
We'll be back in no time. 我们一会儿就回来。
Come and see me in two days' time. 两天后来看我。(从现在开始)
after... (从过去开始)
小处at大处in
例：Li and I arrived at Heishan county safe and sound, all is well. Don't worry. 李和我平安地到达黑山县，一切很好，勿念。
I live in a great city (big city), my sister lives at a small town while my parents live at a village. 我住在大城市，我姐姐住在一个小城镇，而我的父母则住在农村。
I'm in Liaoning, at Anshan. 我住在辽宁省鞍山市．
有形with无形by，语言 、单位、材料in
例：The workers are paving a road with stone. 工人们正用石子铺路。(有形)
The teacher is correcting the paper with a new pen. 这位教师正用一支新笔批改论文。(有形)
"Taking Tiger Mountain by Strategy" is a good opera. <<智取威虎山>>是-出好戏。(无形)
The product is separated by distilation into gasoline and gas oil. 这种产品是用蒸馏分离出气油和粗柴油。 (表示方式、手段、方法--无形)
I really can't express my idea in English freely in-deed． 我确实不能用英语流利地表达我的思想。 (表示某种语言用in)
I wrote a novel in Russian. 我用俄语写了一本小说。(同上)
The kilometer is the biggest unit of length in the metric system． 公里是米制中最长的长度单位。 (表示度、量、衡单位的用in )
The length is measured in meter, kilometre, and centimetre. 长度是以米、公里、厘米为单位来计算的。(同上)
This board was cast in bronze not in gold. 这个牌匾是铜铸的，不是金铸的。
特征、方面与方式、心情、成语惯用in
特征或状态：
例: The Democratic Party was then in power. 那时民主党执政。
They found the patient in a coma. 他们发现病人处于昏迷状态。
He has not been in good health for some years. 他几年来身体一直不好。
Many who came in despair went away in hope. 许多人带着绝望情绪而来，却满怀希望而去。
The house was in ruins. 这房屋成了废墟。
The poor girl was in tears. 这个贫苦女孩泪流满面。
Her clothes were in rags. 她的衣跟穿破了。
His shoes were in holes. 他的鞋穿出窟窿了。
I only said it in fun. 我说这话只是开玩笑的。
She spoke in grief rather than in anger. 与其说她讲得很气愤，不如说她讲得很伤心。
还有一些短语也用in，如：
in jest 诙谐地，in joke 开玩笑地，in spite 恶意地， in fairness 公正地，in revenge 报复, in mercy 宽大，in sorrow 伤心地等。
His mind was in great confusion. 他脑子里很乱。
Today everybody is in high spirits and no one is in low ebb. 今天大家都兴高采烈，没有一个情绪低落的。
She and her classmates are in flower ages. 她和她的同学都正值妙龄。
The compaign was in full swing. 运动正值高潮中。
方面：
例：we accepted the item in principle. 我们在原则上接受了这个条款。
They are never backward in giving their views. 他们从来不怕发表自己的意见。
The backward area has achieved self-sufficient in grain. 这个落后的地区在粮食方面已能自给。
A good teacher must be an example in study. 一个好的教师必须是学习的模范。
方式：
例：All the speeches were taken down in shorthand. 所有报告都用速记记录下来了。
如下成语惯用in
例如： in all 总计
in advance 事前
in the meantime 与此同时
in place 适当地
in hopes of(或in the hope of) 怀着.......希望
in connection with 和……有关
in contact with 和……联系
in addition to 除......以外
in case of 倘若，万一
in conflict with 和......冲突
in force 有效的，大批
in depth 彻底地
in regard to 关于
in the neighborhood of 大约、邻近
in retrospect 回顾，一想起
in behalf of 代表......利益
in the least 一点，丝毫
in alarm 惊慌、担心
in the opinion of 据……见解
in the long run 从长远说来
in one's opinion 在……看来
in word 口头上
in a word 总之
in vain 无益地, 白白地
in case 如果，万一，以防
in detail 详细地
in haste 急急忙忙地
in conclusion 总之
in spite of 尽管
in other words... 换句话说
in return 作为回报
in the name of 以......名义
be confident in 对......有信心
be interested in 对......感兴趣
in doubt 怀疑
in love 恋爱中
in debt 负债
in fun (jest、joke) 玩笑地
in hesitation 犹豫不决
in wonder 在惊奇中
in public (secret) 公开他(秘密地)
in a good humour 心情(情绪)好
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