年、月、年月、季節、周，陽光、燈、影、衣、冒in。
將來時態in...以後，小處at大處in。
有形with無形by，語言、單位、材料in。
特征、方面與方式，心情成語慣用in。
介詞at和to表方向，攻擊、位置、惡、善分。
日子、日期、年月日，星期加上早、午、晚，
收音、農場、值日on，關於、基礎、靠、著論。
著、罷、出售、偷、公、假，故意、支付、相反，準。
特定時日和“壹……就”，on後常接動名詞。
年、月、日加早、午、晚，of之前on代in。
步行、驢、馬、玩笑on，cab，carriage則用in。
at山腳、門口、在當前，速、溫、日落、價、核心。
如大體掌握上面介詞用法口訣，就不易出錯。當然，至於介詞的詳盡用法，同形詞又是連詞及副詞等內容此篇不講。下面對該口訣分別舉例幫助妳理解消化。
早、午、晚要用in
in the evening 在晚上
in the day 在白天
例： in the afternoon 在下午
in the morning 在早上
at黎明、午、夜、點與分
例? at dawn? at daybreak 在黎明時候
at night 在夜間
at noon 在中午
at midnight 在午夜
以上短語都不用冠詞
at nine o'clock 在9點鐘
at 8：30 seven thirty? 在8點半
at half past ten 在10點半
at nine fifteen 在9點15分
at ten thirty a.m. 在上午10點30分
也可以寫成
seven to five 5點差7分半小時以上?
five minutes after two 2點過5分
at the weekend 在周末
at a quarter to two 1點45分
年、月、年月、季節、周
即在“來年”，在“某月”，在“某年某月” 但在某年某月某日則用on?，在四季，在第幾周等都要用in。
例：in 1989 在1989年
in 1927 在1927年
in March 在三月
in April 在四月
in December 1986 在1986年12月
in July l984 在1984年7月
in the first week of this semester這學期的
第壹周
in the third week 在第三周
in spring 在春季 in summer 在夏季
in autumn 在秋季 in winter 在冬季
陽光、燈、影、衣、冒 in
即在陽光下，在燈下，在樹陰下，穿衣、著裝、冒雨等都要用in。
例：Don't write in dim light.切勿在暗淡的燈光
下寫字。
They are reviewing their lessons in the
bright light.他們在明亮的燈光下復習功課。
They are playing in the shade of a tree.
他們坐在樹陰下玩耍。
a prisoner in irons 帶著鐐銬的囚犯
He went in the rain to meet me at the
station. 他冒雨到車站去接我。
The poor in rags in old society. 舊社會窮
人們衣衫襤褸.
以及：in the bright sunlight 在明亮的陽光下
a merchant in disguise 喬裝的商人
the woman in white black? red? yellow?
穿著白黑、紅、黃?色衣服的婦女
in uniform 穿著制服
in mourning 穿著喪服
in red shoes 穿著紅色鞋
in his shirt sleeves 穿著襯衫
將來時態in...以後
例? They will come back in 10 days.
他們將10天以後回來。
I'll come round in a day or two.
我壹兩天就回來。
We'll be back in no time.
我們壹會兒就回來。
Come and see me in three days' time.
三天後來看我。從現在開始?
after... 從過去開始?
小處at大處in
例：Li and I arrived at Heishan county safe and sound? all is well. Don't worry. 李和我平安地到達黑山縣，壹切很好，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，我姐姐住在壹個小城鎮，而我的父母則住在農村。
I'm in Liaoning? at Ashcan. 我住在遼寧省鞍山市.
有形with無形by，語言 、單位、材料in
例：The workers are paving a road with stone.
工人們正用石子鋪路。有形?
The teacher is correcting the paper with a new pen. 這位教師正用壹支新筆批改論文。有形?
〃Taking Tiger Mountain by Strategy〃 is a good opera. 《智取威虎山》是壹出好戲。無形?
The product is separated by distillation into gasoline and gas oil. 這種產品是用蒸餾分離出氣油和粗柴油。 表示方式、手段、方法，無形?
I really can't express my idea in English freely indeed. 我確實不能用英語流利地表達我的思想。 表示某種語言用in?
I wrote a novel in Russian. 我用俄語寫了壹本小說。同上?
The kilometer is the biggest unit of length in the metric system. 公裏是米制中最長的長度單位。 表示度、量、衡單位的用in ?
The length is measured in meter? kilometer? and centimeter. 長度是以米、公裏、厘米為單位來計算的。同上?
This board was cast in bronze not in silver . 這個牌匾是銅鑄的，不是銀制的。
特征、方面與方式、心情、成語慣用in
特征或狀態：
例? They found the patient in a coma. 他們發現病人處於昏迷狀態。
The Democratic Party was then in power. 那時民主黨執政。
He has not been in good health for some years. 他幾年來身體壹直不好。
Many who came in despair went away in hope. 許多人帶著絕望情緒而來，卻滿懷希望而去。
The house was in ruins. 這房屋成了廢墟。
The poor girl was in tears. 這個可憐的女孩淚流滿面。
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. 我說這話只是開玩笑的。
She spoke in grief rather than in anger. 與其說她講得很氣憤，不如說她講得很傷心。
還有壹些短語也用in，如：
in jest 詼諧地，in joke 開玩笑地，in fairness 公正地，in spite 惡意地， in revenge 報復? in mercy 寬大，in sorrow 傷心地等。
His mind was in great confusion. 他腦子裏很亂。
Today everybody is in high spirits and no one is in low ebb. 今天大家都興高采烈，沒有壹個情緒低落的。
She and her classmates are in flower ages. 她和她的同學都正值妙齡。
The campaign was in full swing. 運動正值高潮中。
方面：
例：we accepted the item in principle. 我們在原則上接受了這個條款。
The backward area has achieved self-sufficient in grain. 這個落後的地區在糧食方面已能自給。
A good teacher must be an example in study. 壹個好的教師必須是學習的模範。
They are never backward in giving their views. 他們從來不怕發表自己的意見。
方式：
例：All the speeches were taken down in shorthand. 所有報告都用速記記錄下來了。
The Party has always educated us in the spirit of patriotism and internationalism. 黨壹貫以愛國主義和國際主義精神教育我們。
如下成語慣用in
例： in all 總計
in advance 事前
in addition to 除......以外
in the meantime 與此同時
in place 適當地
in hopes of或in the hope of?懷著.......希望
in connection with 和......有關
in contact with 和......聯系
in case of 倘若，萬壹
in conflict with 和......沖突
in force 有效的，大批
in depth 徹底地
in regard to 關於
in the neighborhood of 大約、鄰近
in retrospect 回顧，壹想起
in alarm 驚慌、擔心
in behalf of 代表......利益
in the least 壹點，絲毫
in the opinion of 據......見解
in the long run 從長遠說來
in one's opinion 在......看來
in a word 總之
in word 口頭上
in vain 無益地? 白白地
in case 如果，萬壹，以防
in detail 詳細地
in haste 急急忙忙地
in conclusion 總之
in spite of 盡管
in other words... 換句話說
in love 戀愛中
in debt 負債
in fun jest、joke? 玩笑地
in hesitation 猶豫不決
in wonder 在驚奇中
in return 作為回報
in the name of 以......名義
be confident in 對......有信心
be interested in 對......感興趣
in doubt 懷疑
in public secret? 公開他秘密地?
in a good humor 心情情緒好
介詞at、to表方向，攻擊、位置、善、惡、分
介詞at和to都可以表示方向。用at表示方向時，側重於攻擊的目標，往往表示惡意；用to表示方向時，突出運動的位置或動作的對象，側重表示善意。試比較下列各句：
1. A. She came at me. 她向我撲過來。
B. She came to me. 她向我走過來。
2. A. Jake ran at John. 傑克向約翰撲過去。
B. Jake ran to John. 傑克朝約翰跑去。
3. A. He rushed at the woman with a sword.
他拿著劍向那婦女撲過去。
B. He rushed to the woman with a sword.
他帶著劍向那婦女跑過去。
4. A. She shouted at the old man.
她大聲喝斥那老人。
B. He shouted to the old man.
他大聲向那老人說
5. A. I heard her muttering at Xiao Li.
我聽見她在抱怨小李。
B. I heard her muttering to Xiao Li.
我聽見她在同小李低聲說話。
6. A. He talked at you just now.
他剛才還說妳壞話呢。
B. She talked to you just now.
她剛才還同妳談話呢.。
7. A. She threw a bone at the dog.
她用壹塊骨頭砸狗。
B. She threw a bone to the dog.
她把壹塊骨頭扔給狗吃。
8. A. He presented a pistol at me.
他用手槍對著我。
B. He presented a pistol to me.
他贈送我壹支手槍。
日子、日期、年月日，星期加上早午晚
以下皆用on
例?on October the first 1949 1949年10月1日
on February the thirteenth l893 1893年2月
13日
on May the first 5月1日
on the sixteenth 16號
on the first 1號
on the second of January 或
on January the second 1月2日
on a summer evening 在夏天的壹個夜晚
on Boxing Day 在節禮日聖誕節次日?
on New Year's Day 在元旦
on my birthday 在我的生日
但 in the Christmas holidays在聖誕節假期? in the eighteenth century 在十八世紀? in ancient times 在古代? in earlier times 在早期? in modern times 在現代，則用in，the present time 現在，at the present day當今則用at。
on May Day 在“五·壹節
on winter day 在冬天
on December 12th 1950 l950年12月12日
on Monday 在星期壹
on Sunday 在星期天
on Tuesday morning 星期二早晨
on Saturday afternoon 星期六下午
on Friday evening 星期五晚上
但last night 昨夜；in the evening 在晚上? on time準時，in time及時，等則不同。
年月日，加早午晚，of之前on代in
例： on the morning of 18th 18日早晨
on the evening of 4th 4日晚上
On the eve of their departure they gave a farewell banquet and their head gave a farewell speech. 他們在臨行前夕舉行了壹次告別宴會，他們的團長發表了告別講話。
收音、農場，值日on
例：Did your supervisor like the story over or on? the radio last night？ 您的導師喜歡昨天從收音機裏聽到的故事嗎？
I heard the news over or on? the radio. 我從收音機裏聽到了這壹條消息。
talk over the radio 由無線電播音
on TV 從電視裏......
Hear something on the wireless
在無線電裏聽到
My brother works on an Army reclamation farm. 我哥哥在壹個軍墾農場工作。
The students are working on a school farm. 學生們正在校辦農場勞動。
This is a farmer's house on a farm.
這是農場的農舍。
Who is on duty? today？ 今天誰值日？
We go on duty at 8 a.m.
我們上午8點鐘上班。
關於、基礎、靠、著論
例? This afternoon we are going to listen to a report on the international situation. 今天下午我們要聽關於國際形勢的報告。
Professor Shen will give us a talk on traveling in America. 沈教授將給我們做關於美國之行的報告。
You are wrong on all these issues. 在這些問題上妳的看法都錯了。
The belief is based on practical experience. 這種信念是以實際經驗為基礎的。
Theory must be based on practice. 理論必須以實踐為基礎。
The people in the south live on rice. 南方人主食大米。靠?
The citizens live on their salaries. 城市人靠薪金生活。
You can't afford luxuries? on an income of 100 Yuan a month. 靠月薪100元的收入，妳是買不起奢侈品的。
Her pet dogs were fed on the choicest food. 她用精飼料餵養她心愛的狗。
He is just a scrounger? who lives on other people. 他正是壹個小偷，專靠損害別人過日子。
Keep the kettle on the boil =boiling?. 讓水壺的水壹直開著。
The enemy are on the run =running?. 敵人在逃跑。
on後接the加上壹個作名詞的動詞.其意義與現在分詞所表達的相近。類似例子很多如：
on the march在行軍中，on the mend 在好轉中，on the prowl徘徊，on the move活動中，on the scrounge巧取豪奪埋語?，on the go活躍，忙碌，on the lookout註意，警戒，on the watch監視著。on the hop趁不備抓住某人等等。
on the People's Democratic Dictatorship《實踐論》和《矛盾論》
on the People's Democratic Dictatorship《論人民民主專政》
〃on Coalition Government〃 《論聯合政府》
著、罷、出售、偷、公、假，故意、支付，相反、準
註：口訣中的著指著火，罷指罷工，偷指偷偷地，公指出差、辦公事；假指休假，準指準時。
例：The house next to mine was on fire. 我鄰居的房子著火了。
The workers of the railway station were on strike. 鐵路工人罷工了。
Grapes and big water melons from Sin kiang are on sale on a large sale. 新疆葡萄和西瓜大量上市了。
do something on the sly quiet?. 秘密地暗地裏，偷偷地?做某事。
I've come here on business. 我是有公事來的。
They went to Bern on a mission. 他們到伯爾尼去執行壹項使命。
They has been away on a long trip. 他們出去做壹次長途旅行。
I'll go home on leave next month. 下月我將休假回家。
I went on business to Shanghai. I did not take leave. 我是公出去上海的，不是不告面別。
She came to see you on purpose. 她是專程來看妳的。
He came here on purpose to discuss it with you. 他到這來是要與妳討論這件事的。
This lunch is on me.
〃No. let's go Dutch.〃
“這頓午飯我付錢。”
“不，還是各付各的”
On the contrary? it was very easy to understand. 相反，這事兒很容易理解。
P1ease come on time. on schedule?. 請準時來。
註：in time是“及時”的意思。
The train arrived on schedule. 火車準時到達。
特定時間和“壹......就”，左右on後動名詞
例：Gases expand on heating and contract on cooling. 氣體加熱時膨脹，冷卻時收縮。特定時間?
On entering the room? he found his friends dancing in high spirits. 壹進屋，他就發現他的朋友們在愉快地跳舞。
On reaching the city he called up Lao Yang. 壹到城裏他就給老楊打了壹個電話。
I'll write to him on hearing from you. 我接到妳的來信就給他寫信。壹......就?
以及on the left? right向左向右，on the stair在臺階上等。
步行、驢、馬、玩笑on，cab，carriage用in
例：On foot步行? on horse騎馬?
on donkey 騎驢。
He rode on? blood flowing from his side. 他騎著馬，鮮血從腰部流下來。
The soldier of the Eighth Route Army rode 100 li on a horse a day in order to catch up with his unit. 為趕上部隊，那位八路軍戰士騎馬日行百裏。
Go on horse back? 騎馬去！
You are having me on? 妳和我開玩笑呢?
in cab和in carriage 不能用on或by cab或carriage。
at山腳、門口在當前，速、溫、日落價核心
即在山腳下、在門口、在目前，速度、以......速率、溫度、在日落時、在......核心要用at。
例：At the foot of the mountain? there are
thirty of our comrades. 在山腳下，有我們30個同誌。
There is a beautiful lake at the foot of the hill. 山腳下有壹個美麗的湖。
At the gate of the house there are many children playing glass ball. 門口有壹大群孩子在玩玻璃球。
Who's standing there at the door？ 誰站在門口？
I don't need the dictionary at present. 我現在還不需要這本詞典。
He is at present in Washington. 他目前正在華盛頓。
The train runs at fifty kilometers an hour. 火車每小時行駛50公裏。
We built the plant at top speed and minimum cost. 我們以最低的投資，最高的速度修建了該工廠。
at home 在國內，在家裏
at ten degrees centigrade 在攝氏10度
at minus ten degrees centigrade 攝氏零下10度
Water freezes at 0°centigrade.水在攝氏零度結冰。
Water usually boils at 100°. 水通常在攝氏l00度沸騰。
at the rate of 49 miles an hour
at full speed 全速
at zero 在零度
at a good price 高價
at a low cost 低成本
at a great cost 花了很大代價
at that time 在當時
Evaporation takes place at all temperatures. 蒸發在任何溫度下都能發生。
at 100RPM revolution per minute? 每分鐘100轉
at a high speed 高速
The soldiers launched an attack upon the enemy at sunset. 戰士們在日落時對敵人發起了攻擊。
at daybreak 日出時
The force at the core leading our cause forward is the Chinese Communist Party. 領導我們事業的核心力量是中國***產黨。
The atom has a nucleus at its core. 在原子的中心有壹個原子核。
At the beginning of this term the teacher in charge of our class was very strict with us. 這學期開始，我們的班主任老師對我們要求非常嚴格。