(1) after与in的用法区别
均可与一段时间连用，after 表示以过去时间为起点的一段时间以后，因此通常与过去时连用；而in则表示从现在算起的一段时间以后，因此通常用于将来时或含有将来意义的句子。如：
He came back after three days. 3天后他回来了。
I’ll come back in three days. 我3天后回来。
I think he can come back in three days. 我想他3天后可以回来。after 除与时间段连用外，还可与时间点连用，此时则可用于将来时(但是in不能与时间点连用)：
He will arrive after five o’clock. 他 5 点钟以后到。
(2)介词in,on与at都可用于表示时间的名词前，但用法各不相同，
其区别在于：
一、用in的场合
（1）表示“在某年/月/季节”这个含义时，须用介词in。例如：
She came to this city in 1980.他于1980年来到这个城市。
It often rains here in summer.夏天这里常常下雨。
（2）表示“从现在起一段时间以后”时，须用介词in。例如：
They will go to see you in a week.他们将在一周后去看望你。
I will be back in a month.我将在一个月后回来。
（3）表示“在某世纪”时，须用介词in.例如:
This machine was invented in the eighteenth century.这台机器是在18世纪发明的.
Great changes took place in the twentieth century.20世纪发生了巨大变化.
（4）表示“在某年代或特定世纪某年代”时，须用介词in。例如：
This incident happened in the 1970''''s.该事件发生在20世纪70年代。
The Anti-Japanese War broke out in the 1930''''s.抗日战争爆发于20世纪30年代。
除此之外，morning / evening / afternoon 三个词也常跟介词in连用。例如：
Don't watch TV too much in the evening.晚上看电视不要太多。
They sometimes play games in the afternoon.他们有时在下午做游戏。
二、用on的场合
（1）表示“在具体的某一天”或“（在具体的某一天的）早上、中午、晚上”等，须用介词on。例如：
Jack was born on May 10th,1982.杰克生于1982年5月10日。
They left on a rainy morning.他们是在一个雨天的早上离开的。
He went back to America on a summer afternoon.他于一个夏天的下午返回了美国。
（2）表示“在星期几”或“在星期几的早上、中午、晚上”等，须用介词on。例如：
We don't go to school on Saturday and Sunday.我们星期六和星期天不上学。
What time do you get up on weekdays?你在平日什么时候起床？
I heard this story on Saturday morning.我是在星期六的早晨听到这个故事的。
（3）表示“在某一节日”时，须用介词on。例如：
We usually eat mooncakes on Mid-autumn Festival.我们通常在中秋节吃月饼。
Mr Hu received a card on Teachers''''Day.胡老师在教师节那天收到了一张卡片。
注意：当morning,evening,afternoon被of短语修饰，习惯上用in,而不用on.例如：
in the early morning of September 10th 在9月10的清晨；in the late afternoon of September 12th 在9月12日的傍晚。
三、用at的场合
（1）表示“某一具体时刻（即几点几分时）”，须用介词at。例如：
He gets up at six o''''clock every day .他每天六点起床。
I got home at five thirty yesterday afternoon.我昨天下午五点半到家。
（2）用在特定的时候（时节、时机）时，须用介词at。例如：
They were happy at that time.他们那时很幸福。
I think the shop is clcsed at this time of day.我认为商店在白天的这个时候关门了。
（3）表示“在中午、在夜晚、在周末”时，须用介词at。例如：
What do you often do at noon?你中午经常做些什么？
You can see many stars in the sky at night.夜晚你能看到天空中有许多星星。
（4）表示“在……岁”时，须用介词at。例如：
At the age of nine ,the boy could swim well.在九岁的时候，这孩子就游泳游得很好了。
At the age of twenty,I began to teach English at this school.在二十岁的时候，我就开始在这所学校教英语了。
注意：在含有next ,last,this,one ,any, each, every , some, all 的词组和tomorrow,yesterday, the day after tomorrow, the day before yesterday 前不用任何介词。例如：
What did you do last summer holidays?去年暑假你做了些什么？
What are you going to do the day after tomorrow?后天你打算做什么? 早、午、晚要用in，at黎明、午夜、点与分。
年、月、年月、季节、周，阳光、灯、影、衣、冒in。
将来时态in...以后，小处at大处in。
有形with无形by，语言、单位、材料in。
特征、方面与方式，心情成语惯用in。
介词at和to表方向，攻击、位置、恶、善分。
日子、日期、年月日，星期加上早、午、晚，
收音、农场、值日on，关于、基础、靠、著论。
着、罢、出售、偷、公、假，故意、支付、相反，准。
特定时日和“一……就”，on后常接动名词。
年、月、日加早、午、晚，of之前on代in。
步行、驴、马、玩笑on，cab，carriage则用in。
at山脚、门口、在当前，速、温、日落、价、核心。
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、点与分
例at dawn at daybreak 在黎明时候
at night 在夜间
at noon 在中午
at midnight 在午夜
以上短语都不用冠词
at nine o'clock 在9点钟
at 8：30 seven thirty 在8点半
at half past ten 在10点半
at nine fifteen 在9点15分
at ten thirty a.m. 在上午10点30分
也可以写成
seven to five 5点差7分半小时以上
five minutes after two 2点过5分
at the weekend 在周末
at a quarter to two 1点45分
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 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这学期的
第一周
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
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 write in dim light.切勿在暗淡的灯光
下写字。
They are reviewing their lessons in the
bright light.他们在明亮的灯光下复习功课。
They are playing in the shade of a tree.
他们坐在树阴下玩耍。
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 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 red shoes 穿着红色鞋
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 three days' time.
三天后来看我。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 Ashcan. 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》是一出好戏。无形
The product is separated by distillation 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 indeed. 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 kilometer and centimeter. 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 silver . 这个牌匾是铜铸的，不是银制的。
特征、方面与方式、心情、成语惯用in
特征或状态：
例They found the patient in a coma. 他们发现病人处于昏迷状态。
The Democratic Party was then in power. 那时民主党执政。
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. 这个可怜的女孩泪流满面。
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 fairness 公正地，in spite 恶意地，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 campaign 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。
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。
They are never backward in giving their views. 他们从来不怕发表自己的意见。
方式：
例：All the speeches were taken down in shorthand. 所有报告都用速记记录下来了。The Party has always educated us in the spirit of patriotism and internationalism. 党一贯以爱国主义和国际主义精神教育我们。
如下成语惯用in
例：in all 总计
in advance 事前
in addition to 除......以外
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 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 alarm 惊慌、担心
in behalf of 代表......利益
in the least 一点，丝毫
in the opinion of 据......见解
in the long run 从长远说来
in one's opinion 在......看来
in a word 总之
in word 口头上
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 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 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 public secret 公开他秘密地
in a good humor 心情情绪好
介词at、to表方向，攻击、位置、善、恶、分
介词at和to都可以表示方向。用at表示方向时，侧重于攻击的目标，往往表示恶意；用to表示方向时，突出运动的位置或动作的对象，侧重表示善意。试比较下列各句：
1. A. She came at me. 她向我扑过来。
B. She came to me. 她向我走过来。
2. A. Jake ran at John. 杰克向约翰扑过去。
B. Jake ran to John. 杰克朝约翰跑去。
3. A. He rushed at the woman with a sword.
他拿着剑向那妇女扑过去。
B. He rushed to the woman with a sword.
他带着剑向那妇女跑过去。
4. A. She shouted at the old man.
她大声喝斥那老人。
B. He shouted to the old man.
他大声向那老人说
5. A. I heard her muttering at Xiao Li.
我听见她在抱怨小李。
B. I heard her muttering to Xiao Li.
我听见她在同小李低声说话。
6. A. He talked at you just now.
他刚才还说你坏话呢。
B. She talked to you just now.
她刚才还同你谈话呢.。
7. A. She threw a bone at the dog.
她用一块骨头砸狗。
B. She threw a bone to the dog.
她把一块骨头扔给狗吃。
8. A. He presented a pistol at me.
他用手枪对着我。
B. He presented a pistol to me.
他赠送我一支手枪。
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号
on the first 1号
on the second of January 或
on January the second 1月2日
on a summer evening 在夏天的一个夜晚
on Boxing Day 在节礼日圣诞节次日
on New Year's Day 在元旦
on my birthday 在我的生日
但in the Christmas holidays在圣诞节假期in the eighteenth century 在十八世纪in ancient times 在古代in earlier times 在早期in modern times 在现代，则用in，the present time 现在，at the present day当今则用at。
on May Day 在“五·一节
on winter day 在冬天
on December 12th 1950 l950年12月12日
on Monday 在星期一
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准时，in time及时，等则不同。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. 他们在临行前夕举行了一次告别宴会，他们的团长发表了告别讲话。
收音、农场，值日on
例：Did your supervisor like the story over or on the radio last night？您的导师喜欢昨天从收音机里听到的故事吗？
I heard the news over or on the radio. 我从收音机里听到了这一条消息。
talk over the radio 由无线电播音
on TV 从电视里......
Hear something on the wireless
在无线电里听到
My brother works on an Army reclamation farm. 我哥哥在一个军垦农场工作。The students are working on a school farm. 学生们正在校办农场劳动。
This is a farmer's house on a farm.
这是农场的农舍。
Who is on duty today？今天谁值日？
We go on duty at 8 a.m.
我们上午8点钟上班。
关于、基础、靠、著论
例This afternoon we are going to listen to a report on the international situation. 今天下午我们要听关于国际形势的报告。
Professor Shen will give us a talk on traveling in America. 沈教授将给我们做关于美国之行的报告。
You are wrong on all these issues. 在这些问题上你的看法都错了。
The belief is based on practical experience. 这种信念是以实际经验为基础的。Theory must be based on practice. 理论必须以实践为基础。
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，你是买不起奢侈品的。
Her pet dogs were fed on the choicest food. 她用精饲料喂养她心爱的狗。
He is just a scrounger who lives on other people. 他正是一个小偷，专靠损害别人过日子。
Keep the kettle on the boil =boiling . 让水壶的水一直开着。
The enemy are on the run =running . 敌人在逃跑。
on后接the加上一个作名词的动词.其意义与现在分词所表达的相近。类似例子很多如：
on the march在行军中，on the mend 在好转中，on the prowl徘徊，on the move 活动中，on the scrounge巧取豪夺埋语，on the go活跃，忙碌，on the lookout 注意，警戒，on the watch监视着。on the hop趁不备抓住某人等等。
on the People's Democratic Dictatorship《实践论》和《矛盾论》
on the People's Democratic Dictatorship《论人民民主专政》
〃on Coalition Government〃《论联合政府》
着、罢、出售、偷、公、假，故意、支付，相反、准
注：口诀中的着指着火，罢指罢工，偷指偷偷地，公指出差、办公事；假指休假，准指准时。
例：The house next to mine was on fire. 我邻居的房子着火了。
The workers of the railway station were on strike. 铁路工人罢工了。
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 has 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，不是不告面别。
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.
〃No. let's go Dutch.〃
“这顿午饭我付钱。”
“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。
注：in time是“及时”的意思。
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。
On reaching the city he called up Lao Yang. 一到城里他就给老杨打了一个电话。I'll write to him on hearing from you. 我接到你的来信就给他写信。一......就
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：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 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 kilometers 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l00度沸腾。
at the rate of 49 miles an hour
at full speed 全速
at zero 在零度
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 100RPM revolution per minute 每分钟100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。
for
1. prep.
(1)因为，由于for this reason
(2) 表示时间\距离长度；for three days；He ran for three miles.
(3) 为了：What do you come here for?
(4) 表示等价交换：He sold his house for 30,000 dollars.
(5) 开往；前往We set off for London.
(6) 代；替；代表Red is for danger.
(7) 用于for + 名词或代词+ to + 不定式动词的名词短语中
The bell rang for the lesson to begin.
2. conj 因为（表示推测或附加的原因，前后为并列句）
It must have rained last night, for the ground is wet.
Kuntta ( a prisoner ) knew day broke, for he heard the birds singing.
尽管for 的用法较多，但记住常用的几个就可以了。
It is time for 的用法
[ 标签：it is,time,用法 ]
比如It is time for the bed 对吗
后面不加the
一般是It is time for doing sth/加名词
如It is time for bed.
it 的基本用法
⑴. 用作人称代词，代替前文提到过的事物。
The train has arrived. It arrived half an hour ago.
⑵. 用以代替提示代词this, that。
—What’s this?
—It’s a knife.
— Whose watch is that?
—It’s mine.
⑶. 起指示代词的作用，指一个人或事物。
— Who is knocking at the door?
—It’s me.
⑷. 指环境情况等。
It was very noisy (quiet) at the very moment.
⑸. 指时间、季节等。
— What time is it?
—It’s eight o’clock.
It often rains in summer here.
⑹. 指距离。
It is a long way to the school.
⑺. 作形式主语。
It is not easy to finish the work in two days.
It is no use crying over spilt milk.
It is as pity that you didn’t read the book.
⑻.作形式宾语。
I think it no use arguing with him.
I found it very interesting to study English.
He made it clear that he was not interested in that subject.
⑼. 用于强调结构。
It was Xiaoming whom(that)I met in the street last night.
It was in the street that I met Xiaoming last night.
It ws last night that I met Xiaoming in the street.
It was I who met Xiaoming in the street last night.
2、含有“It is …”的句型
⑴. It is time ( for sb. ) to do sth.
It is ( high ) time that sb. did sth. ( 虚拟语气 )
⑵. It is + 形容词（ +of / for sb. ）+ to do sth.
通常用 of的词有brave、clever、careful、hopeless、kind、good、nau ghty、nice、silly、stupid、foolish、wise等。
⑶. It is + 形容词 + that + sb. + ( should ) do sth.（虚拟语气）
能用于这个句型的形容词有strange、wonderful、natural、good、proper、ri ght、wrong、well、fortunate、important、necessary、useless、likely、p robable、impossible等。有时可省去should而直接用动词原形。如：
It is important that we should pay close attention to grain.
It is natural that he（should）say so.
⑷. It is no use / good + doing sth.
It is no use trying again = It is of no use to try again.
⑸. It is + 被强调部分 + that / w ho + …
Was it in the street that you met her?
Who was it that called him“comrade”?
It was not until yesterday that I met my old friend.
It is in a small factory that my brother is going to work.
（注意上述各句均为强调句型的“考点”）
比较：
It is a small factory where my brother is going to work.
（定语从句）
⑹. It is said /reported / announced / ( well ) known … that…
⑺. It is/was + 时间+ since … 从……已多久了。
It is three years since I met him in Beijing.
It was a long time since I (had) lived in that small mountain villa ge with these farmers.
（注意两句中的时态）
It is five months since I arrived in New York.
我到纽约已经五个月了。
It is five months since I was in New York.
我离开纽约已经五个月了。
（注意：终止性动词表示从动作发生时算起；如果是状态动词或持续性动词，则从动作或状态结束时算起。）
⑻ .It is + 时间+ before …
这个句型和上面句型中时间都是时间段，如long、years、months、weeks、f ive days、three hours、twenty minutes等。不过主句的时态多用一般将来时或一般过去时。
It will be several years before we meet again.
我们要过好几年才能再见面。
It was not long before they set out for the front.
不久他们就出发去了前线。
⑼. It is /was/will be the first/second/third … time that …
It is the first time that I have been here.
It was the second time that he had seen the film.
⑽. It is up to sb. to do sth … 应由某人做某事。
It is up to you to decide whether w1. it 的基本用法
⑴. 用作人称代词，代替前文提到过的事物。
The train has arrived. It arrived half an hour ago.
⑵. 用以代替提示代词this, that。
—What’s this?
—It’s a knife.
— Whose watch is that?
—It’s mine.
⑶. 起指示代词的作用，指一个人或事物。
— Who is knocking at the door?
—It’s me.
⑷. 指环境情况等。
It was very noisy (quiet) at the very moment.
⑸. 指时间、季节等。
— What time is it?
—It’s eight o’clock.
It often rains in summer here.
⑹. 指距离。
It is a long way to the school.
⑺. 作形式主语。
It is not easy to finish the work in two days.
It is no use crying over spilt milk.
It is as pity that you didn’t read the book.
⑻.作形式宾语。
I think it no use arguing with him.
I found it very interesting to study English.
He made it clear that he was not interested in that subject.
⑼. 用于强调结构。
It was Xiaoming whom(that)I met in the street last night.
It was in the street that I met Xiaoming last night.
It ws last night that I met Xiaoming in the street.
It was I who met Xiaoming in the street last night.
2、含有“It is …”的句型
⑴. It is time ( for sb. ) to do sth.
It is ( high ) time that sb. did sth. ( 虚拟语气 )
⑵. It is + 形容词（ +of / for sb. ）+ to do sth.
通常用 of的词有brave、clever、careful、hopeless、kind、good、nau ghty、nice、silly、stupid、foolish、wise等。
⑶. It is + 形容词 + that + sb. + ( should ) do sth.（虚拟语气）
能用于这个句型的形容词有strange、wonderful、natural、good、proper、ri ght、wrong、well、fortunate、important、necessary、useless、likely、p robable、impossible等。有时可省去should而直接用动词原形。如：
It is important that we should pay close attention to grain.
It is natural that he（should）say so.
⑷. It is no use / good + doing sth.
It is no use trying again = It is of no use to try again.
⑸. It is + 被强调部分+ that / who + …
Was it in the street that you met her?
Who was it that called him“comrade”?
It was not until yesterday that I met my old friend.
It is in a small factory that my brother is going to work.
（注意上述各句均为强调句型的“考点”）
比较：
It is a small factory where my brother is going to work.
（定语从句）
⑹. It is said /reported / announced / ( well ) known … that…
⑺. It is/was + 时间+ since … 从……已多久了。
It is three years since I met him in Beijing.
It was a long time since I (had) lived in that small mountain villa ge with these farmers.
（注意两句中的时态）
It is five months since I arrived in New York.
我到纽约已经五个月了。
It is five months since I was in New York.
我离开纽约已经五个月了。
（注意：终止性动词表示从动作发生时算起；如果是状态动词或持续性动词，则从动作或状态结束时算起。）
⑻ .It is + 时间+ before …
这个句型和上面句型中时间都是时间段，如long、years、months、weeks、f ive days、three hours、twenty minutes等。不过主句的时态多用一般将来时或一般过去时。
It will be several years before we meet again.
我们要过好几年才能再见面。
It was not long before they set out for the front.
不久他们就出发去了前线。
⑼. It is /was/will be the fi rst/second/third … time that …
It is the first time that I have been here.
It was the second time that he had seen the film.
⑽. It is up to sb. to do sth … 应由某人做某事。
It is up to you to decide whethe e start or not.
after用法小议 通常用于过去时、现在时（主将从现）或完成时态的句子中。 1. 1. 用作介词，与一段时间连用表示“在…之后”时，注意它与 in的区别：after表示以过去时间为起点的一段时间以后，且通常与过去时态连用；而in则表示以现在为起点的一段时间以后：He came back after two days. 他两天后就回来了。He will come back in two days. 他过两天就回来。但 after 若是与一点时间连用，则可与过去时态也可与将来时态连用：He came back after 4 o’clock. 他是四点钟以后回来的。 He will come back after next month. 他将在下个月以后回来。 eg. 2. I played computer games after I had finished my homework. 做完功课后，我玩电脑游戏。(从句的动作发生在主句的动作前，因此，主句用一般过去式，从句用过去完成时．) Before和after引导的时间状语从句中，由于before和after 本身的词义已经能够表明动作发生的先后，所以主句可以用一般时代替完成时，也可以用完成时。 I knew/had known her long before you knew her.我认识她早在你认识他之前。 After you finish/have finished all your homework,you can watch TV this evening.你完成所有的作业后，今晚可以看电视。
2. 用作连词引导时间状语从句时注意：若主句用将来时态 (或含有将来意味)，则时间状语从句要用一般现在时态 (表将来意义)表将来意义，而不能直接使用将来时态：他回来后我就走。正：I’ll leave after he comes back. 误：I’ll leave after he will come back. 3. 用作副词，表示“后来”、“ (一段时间)以后”，通常放在表示时间的副词之后：soon after 不久以后 two days after两天后 The plane was hijacked soon after it took off. Two days later he was gone. 4. 用于习语after all 终究，毕竟：I was right after all. 毕竟我是对的。After all, he’s only six years old. 毕竟，他才六岁。 before用法小结 请先看2005年广东省的一道高考题： The American Civil War lasted four years _______ the North won in the end. A. after B. before C. when D. then
一、before与ago的区别 1.ago表示“从现在起的若干时间以前”，意思是“距今……以前”，需和过去时或过去进行时连用。before泛指“从过去起的若干时间以前”，意思是“距过去某时……以前”“与其……（毋宁）”，常和完成时连用，尤其在间接引语中，如：I visited him three days ago, but he had gone to Shanghai a week before．我三天前去访问他，但他已与那时的一周前到上海去了。 His parents died ten years ago．他父母十年前都去世了。 He said that his parents had died ten years before．他说他父母亲十年前都去世了。 I have never been there before．我以前从来没有去过那里。 2.如果不具体表明多少时间以前，只用before不用ago，意为“从前、以前”。before仍以副词的形式置于被修饰语后，常与完成时候过去时连用。如： Have you seen this film before? He asked me whether I had been to the Great Wall before． 3.表示在某一点时间或事件以前时，只用before不用ago，这种用法是将before当作介词或连词使用。ago不具有这一功能。如： They will come back before six o’clock． It is hoped that this will be finished before the year 1995．希望这件工作将在1995年以前完成。 另外，before在句中的含义较多。不少句子中，before虽然引导的也是一个时间状语，但是译成汉语时却不必译为“在……以前”。 a.如果before引导的从句动作发生得晚或慢，可译成“……才”。这是主句主语或是名词、代词，或用it作形式主语． He had almost knocked me down before he saw me．他几乎把我撞倒才看见我。 It will be hours before he arrives．要过几个钟头他才回到达。 You must sow before you can reap．有播种才能有收成。 b.如果强调从句动作发生之前，主句动作已发生，可译成“未……就”或“还没有……就”。
With的用法全解 with结构是许多英语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。本文就此的构成、特点及用法等作一较全面阐述，以帮助同学们掌握这一重要的语法知识。 一、 with结构的构成 它是由介词with或without+复合结构构成，复合结构作介词with或without的复合宾语，复合宾语中第一部分宾语由名词或代词充当，第二部分补足语由形容词、副词、介词短语、动词不定式或分词充当，分词可以是现在分词，也可以是过去分词。With结构构成方式如下： 1. with或without-名词/代词+形容词； 2. with或without-名词/代词+副词； 3. with或without-名词/代词+介词短语； 4. with或without-名词/代词 +动词不定式； 5. with或without-名词/代词 +分词。 下面分别举例： 1、 She came into the room，with her nose red because of cold.（with+名词+形容词，作伴随状语）
2、 With the meal over ， we all went home.（with+名词+副词，作时间状语） 3、The master was walking up and down with the ruler under his arm。（with+名词+介词短语，作伴随状语。） The teacher entered the classroom with a book in his hand. 4、He lay in the dark empty house，with not a man ，woman or child to say he was kind to me.（with+名词+不定式，作伴随状语）He could not finish it without me to help him.（without+代词 +不定式，作条件状语） 5、She fell asleep with the light burning.（with+名词+现在分词，作伴随状语） Without anything left in the with结构是许多英 语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。本文就此的构成、特点及用法等作一较全面阐述，以帮助同学们掌握这一重要的语法知识。 二、with结构的用法 with是介词，其意义颇多，一时难掌握。为帮助大家理清头绪，以教材中的句子为例，进行分类，并配以简单的解释。在句子中with结构多数充当状语，表示行为方式，伴随情况、时间、原因或条件（详见上述例句）。 1.带着，牵着…… (表动作特征)。如： Run with the kite like this.
after的用法 1.用作连词是词，它引导的时间状语从句如果具有将来意义，往往要用一般现在时来表示(有时也用现在完成时)，而不能直接用一般将来时。如： 误：I’ll tell him after you wil leave. 正：I’ll tell him after you leave (或have left). 你走了之后我再告诉他。 注：(1)具有以上性质的时间连词还有when, as soon as, until 等以及条件连词if。 (2)选择一般现进或现在完成进(表示将来意义)的基本原则是：如果强调从句动作在主句动作之前完成，则用现在完成时；如果强调主从句动作同时发生，或几乎同时发生(尤其是当从句的谓语动词是get, arrive, see, hear, leave, return等表示迅速完成的动作的动词时)，多用一般现在时(有时两种时态都可以)。如； I’ll leave when he comes back. 他回来后我就离开。(from https://www.doczj.com/doc/2615852596.html,) I will give my opinion when I have read the book through. 我把书看完了再提意见。 We’ll leave as soon as it stops (或has stopped) raining. 雨停我们就动身。 2.一般说来，如果在过去某一时间内先后发生了两个动作，那么先发生的动作用过去完成时，后发生的动作用一般过去时。但是若用连词after 来连接这两个动作，由于after 本身已说明了两个动作的先后关系，所以两者均可用一般过去时。如： After he (had) closed the door, he left the house. 关了门之后，他就离开了家。 注：类似这种性质的时间连词还有before, as soon as等。 3.有时以连词after引导的时间状语从句可以换成一个以介词after引导介词短语或以连词after引导的分词短语，而意义不变。如： He went to school after he had breakfast (=after breakfast). 吃了早饭之后，他就去上学了。 After l had finished (=After having finished / After finishing / Having我干完活后就去睡觉了。 4.after还可用作副词，意为“后来”或“(一段时间)以后”，通常要放在另一时间副词之后。如： We arrived soon (或just / shortly) after. 我们不久就到了。 He returned twenty years after. 20年后他回来了。 注：(1)在非正式文体中，after也可放在其它词之后。如： We had dinner and went home after. 我们吃了饭，后来就回家了。 (2)two days after=after two days=two days later.
before的用法是很多的人都比较想要了解的，在众人的心中before的用法是比较难的，我们都非常想要去了解before的用法，但是又谈何容易呢?为了让大家更加快速的了解before的用法，下面我们就和教师一起去看看吧，希望对大家有所帮助。 prep.在……之前;先于，优于;当着……的面;与其…… conj.在……之前;在……以前;比……早些;与其…… adv.先前，从前;在前，在前方 before一词含义广泛，是高考考查的热点词汇之一，但部分考生对该词的用法模糊不清。为了帮助大家掌握，现就对before的用法归纳如下： 一、before用作连词 1. before用作连词时，意思是“在……之前;还没来得及…… 就”。强调主句或从句谓语动词表示的动作发生得过早或过快?例如： Before she could move, she heard a great noise, which grew to a terrible roar. 她还没来得及动弹，就听见有很响的声音，接着就成了可怕的隆隆轰鸣声。 Before I could say a word, she had stormed out of the room. 不等我说一句话，她就冲出了房间。 Don’t count your chickens before they are hatched. 不要高兴得过早。 I must finish my homework before I watch TV.我必须做完作业才能看电视。 It still took seven years before they finally got married. 过了七年他们才最终得以成婚。 It will be only a few minutes before she comes back. 她过几分钟就会回来。 He announced the ending of the meeting before I could get in a word. 没容得我插上一句话,他就宣布散会了? Someone called me up in the middle of the night, but they hung up before I could answer the phone.有人半夜给我打电话,但我还未来得及接他就把电话挂断了? They had talked only a few minutes before they found they were quite different in opinion.他们才谈了几分钟就发现他们的意见很不一致? 注意：before从句若是一个将来的动作，则用一般现在时代替一般将来时，如上句中的comes。 2. 用于It + be + 时间段+ before...句型中，意思是“在……之后才……”。例
详解ago与before的语法难点 1. before还是ago? 要说： I came to Manchester two weeks ago.I came to Manchester two weeks ago. 不要说： I came to Manchester before two weeks. Use past time + ago ago用于一般过去时，例如： 10 years ago, a long time ago, a few weeks ago, a couple of days ago Use before + action / event before用于动作或事件前，例如： before you left, before we start, before lunch 2. fall 还是reduce? These two words are the opposites of rise and raise: 它们是rise和raise的反义词： something falls (e.g. the price fell) somebody reduces something (e.g. the company reduced the price) You will probably use fall to describe numbers on a graph
or chart for IELTS Writing Task 1: 在雅思短作文中，你可以用fall来描述图表里的数字。 In 2008, the number of customers fell. (verb, past) 这里的fall是动词，过去时。 There was a sharp fall in Internet usage. (noun) 这里的fall是名词。 Reduce and reduction are probably more useful for Writing Task 2: reduce和reduction在长作文中更有用： We need to reduce the amount of pollution from exhaust fumes. (verb) reduce，动词。 Recycling leads to a reduction in waste. (noun) reduction，名词。 3. because还是because of? Compare these two sentences: 比较下列两个句子： I stayed at home because the weather was bad. I stayed at home because of the bad weather. The important difference is the use of the word was in the first sentence. After because, you need a subject and a verb (e.g. the weather was). After because of, we dont use a verb,
with用法归纳 （1）“用……”表示使用工具，手段等。例如： ①We can walk with our legs and feet. 我们用腿脚行走。 ②He writes with a pencil. 他用铅笔写。 （2）“和……在一起”，表示伴随。例如： ①Can you go to a movie with me? 你能和我一起去看电影'>电影吗？ ②He often goes to the library with Jenny. 他常和詹妮一起去图书馆。 （3）“与……”。例如： I’d like to have a talk with you. 我很想和你说句话。 （4）“关于，对于”，表示一种关系或适应范围。例如： What’s wrong with your watch? 你的手表怎么了？ （5）“带有，具有”。例如： ①He’s a tall kid with short hair. 他是个长着一头短发的高个子小孩。 ②They have no money with them. 他们没带钱。 （6）“在……方面”。例如： Kate helps me with my English. 凯特帮我学英语。 （7）“随着，与……同时”。例如： With these words, he left the room. 说完这些话，他离开了房间。 [解题过程] with结构也称为with复合结构。是由with+复合宾语组成。常在句中做状语，表示谓语动作发生的伴随情况、时间、原因、方式等。其构成有下列几种情形： 1.with+名词(或代词)+现在分词 此时，现在分词和前面的名词或代词是逻辑上的主谓关系。 例如:1)With prices going up so fast, we can't afford luxuries. 由于物价上涨很快，我们买不起高档商品。（原因状语） 2)With the crowds cheering, they drove to the palace. 在人群的欢呼声中，他们驱车来到皇宫。（伴随情况） 2.with+名词(或代词)+过去分词 此时，过去分词和前面的名词或代词是逻辑上的动宾关系。
2021届新高考语法讲义before after引导的时间状语从句的用法知识点整理总结 今天我们继续学习时间状语从句的引导词before和after。二者的时态问题是困扰很多同学的难点，今天我就重点来谈谈。 01 before/after用法概述 b e f o re/af te r引导时间状语从句，表示主从句的时间顺序：“在…之前”或“在…之后”。二者时态主要有以下2种情况： 主将从现 01 当主句是一般将来时（或祈使句、含有情态动词的句子）时，从句一般用现在时（一般现在/现在进行/现在完成）。这种主从句时态关系一般称为“主将从现”。 如： It won't be long before we meet again. 我们后会有期！ He will be a teacher after he graduates from college. 他大学毕业后将去做教师。 主过从过 02
当主句和从句的动作都是过去，且二者发生时间相同或前后差别不大时，主从句都用一般过去时；如果要强调一个在另一个之前，那么就要用过去完成时（也即两个过去）。 如（仅以before举例，after例子见后）： He worked in Beijing before he came here. 他来这里之前在北京工作！ He had studied Chinese for one year before he came to China. 他来中国之前学了一年中文。 02 before的用法 before除了基本的表示“在…之前”的意思外，还能表示以下几种意思： 表示“还未…就…”，主从都用一般过去时 这种情况下，before强调主句动作较从句动作发生的过早或过快。但时间相差不大，因此主从句都用一般过去时。 He called me up at midnight but hung up before I could answer it. 我还未来得及接电话，他就给挂了。 表示“…才…”，主从都用一般过去时
ago 只作副词，必须与一段时间连用，表示以现在为起点一段时间之前。before既可以作副词也可以作连词。作副词时，可以单独使用;也可以和一段时间的词连用，表示的是已过去某个时间为起点一段时间之前。 ago 和before的区别 1、意思不同 ago 表示“从现在起若干时间以前”。 before 表示“从过去某时起若干时间以前”。 2、词性不同 ago只能作副词。 例句： She left England three days ago. 她三天前离开了英格兰。 before既可作副词又可作介词和连词。 例句： Please close the window before you leave. 离开前请关好窗户。(连词) 3、后接单词不同 ago常与动词一般过去式连用。 例句： His grandfather died two years ago. 他的外公两年前去世了。 before常与过去完成式连用。
例句： I had finished the work two days before. 两天前我就已经完成了工作。 ago的用法 1、用于一般过去时。 例句： A short while ago, my sister helped me to carry one of my old bookcases up the stairs. 片刻之前，我妹妹帮我把我的一个旧书柜抬上了楼。 2、所指的时间是从现在算起。 例句： It was stolen twenty years ago when Ted was a boy of fifteen. 那辆自行车是在20年前当泰德还是个15岁的小伙子时被偷去的。 before的用法 1、用于过去完成时 例句： A short time before, great trees had covered the countryside for miles around. 在那时不久之前，高大的树木覆盖着方圆数英里的地方。 2、它所指的时间不是从现在算起，而是从过去某一时刻算起，有时可以与previously 换用 例句： Last summer, I finally left the firm that I had joined eighteen years
独立主格篇 独立主格，首先它是一个“格”，而不是一个“句子”。在英语中任何一个句子都要有主谓结构，而在这个结构中，没有真正的主语和谓语动词，但又在逻辑上构成主谓或主表关系。独立主格结构主要用于描绘性文字中，其作用相当于一个状语从句，常用来表示时间、原因、条件、行为方式或伴随情况等。除名词/代词+名词、形容词、副词、非谓语动词及介词短语外，另有with或without短语可做独立主格，其中with可省略而without不可以。*注：独立主格结构一般放在句首，表示原因时还可放在句末；表伴随状况或补充说明时，相当于一个并列句，通常放于句末。 一、独立主格结构： 1. 名词/代词+形容词 He sat in the front row, his mouth half open. Close to the bank I saw deep pools, the water blue like the sky. 靠近岸时，我看见几汪深池塘，池水碧似蓝天。 2. 名词/代词+现在分词 Winter coming, it gets colder and colder. The rain having stopped, he went out for a walk.
The question having been settled, we wound up the meeting. 也可以The question settled, we wound up the meeting. 但含义稍有差异。前者强调了动作的先后。 We redoubled our efforts, each man working like two. 我们加倍努力，一个人干两个人的活。 3. 名词/代词+过去分词 The job finished, we went home. More time given, we should have done the job much better. *当表人体部位的词做逻辑主语时，不及物动词用现在分词，及物动词用过去分词。 He lay there, his teeth set, his hands clenched, his eyes looking straight up. 他躺在那儿，牙关紧闭，双拳紧握，两眼直视上方。 4. 名词/代词+不定式 We shall assemble at ten forty-five, the procession to start moving at precisely eleven. We divided the work, he to clean the windows and I to sweep the floor.
before和ago都能表示在一段时间以前，但是二者的内涵和具体用法有明显的区别： 1. before表示从过去或将来某一时间算起多少时间以前，由于与这一时间状语连用的行为先发生在过去或将来某一时刻之前，因此往往出现在过去完成时态或将来完成时态中。例如： ①I called him up last night，but his mother told me he had left for Wuhan two days before. ②She said that she had married him five years before. 2.如果不具体表明多少时间以前，before意为"从前；以前"，表示从现在开始追溯到过去一段时间，或者主句的谓语动词表示的是经常、反复发生的行为，以副词的形式置于句末，可以用在现在完成时态中。例如： ①I have never been to Beijing before. ②Have you ever seen a tiger before? ③I often go over the lessons that I have learned a few days before. 注意：before前的时间状语如果是特定的，含义不一样。试比较： He said he had arrived here a day before. (一天前) He said he had arrived here the day before. (前一天) 3. ago指的是从现在起到过去时间的某一点的一段时间。这个时间状语常与一般过去时态或过去进行时态连用。例如： ①I graduated from the college twenty years ago. ②I was asked what I was doing a month ago. 4. 表示在某一时间点或事件以前时，只能用before，不用ago。因为这种用法是将before当作介词或连词使用。ago不具有这种功能。例如： ①He will come back before eleven o'clock.
with用法小结 一、with表拥有某物 Mary married a man with a lot of money . 马莉嫁给了一个有着很多钱的男人。 I often dream of a big house with a nice garden . 我经常梦想有一个带花园的大房子。 The old man lived with a little dog on the lonely island . 这个老人和一条小狗住在荒岛上。 二、with表用某种工具或手段 I cut the apple with a sharp knife . 我用一把锋利的刀削平果。 Tom drew the picture with a pencil . 汤母用铅笔画画。 三、with表人与人之间的协同关系 make friends with sb talk with sb quarrel with sb struggle with sb fight with sb play with sb work with sb cooperate with sb I have been friends with Tom for ten years since we worked with each other, and I have never quarreled with him . 自从我们一起工作以来，我和汤姆已经是十年的朋友了，我们从没有吵过架。 四、with 表原因或理由 John was in bed with high fever . 约翰因发烧卧床。 He jumped up with joy . 他因高兴跳起来。 Father is often excited with wine . 父亲常因白酒变的兴奋。 五、with 表“带来”，或“带有,具有”，在…身上，在…身边之意
before用法知多少？ 在高考中，状语从句是每年高考单项填空部分必考的题目之一，考查的重点是考生容易混淆并且近似的连词在逻辑行文和语篇结构中的使用。before作连词的用法一直是高考的重点，也是学生感觉掌握起来比较头疼的地方。下面选取近几年各省市的高考试题进行归纳分析，使考生通过典型实例，把握高考对before所引导的句型的命题规律，帮助同学们更好地解答此类题目。 1. before作为连词时的基本意义是“在……之前”，用于表示时间或顺序。 You can’t borrow books from the school library ______ you get your student card. (2009上海，32) A. before B. if C. while D. as 【解析】选A。考查连词，该句的意思是：在你得到你的学生卡之前你不能从学校图书馆借书。before表示先后顺序。 2. 表示“过了多久才……”，说明主句的持续时间比较长而从句的动作缓缓来迟。 (1) The American Civil War lasted four years _______ the North won in the end. (2005广东，30) A. after B. before C. when D. then 【解析】选B。本题考查连词before表示“在多久之后才……”的用法，根据本句含义“美国南北战争持续了四年，北方才最终取得胜利”，可知本题应选B。 (2) Several weeks had gone by I realized the painting was missing. (2004宁夏，39) A. as B. before C. since D. when 【解析】选B。before表示“过多久才……”。句意：几个星期已经过去了，我才意识到油画丢了。内含的意思是油画丢了好几个星期了，我才意识到。 3. 表示从句动作还没来得及发生或完成，主句动作就已经发生或完成了，意为“尚未……就”，“没来得及……就”，常用于before sb. can/ could…。 —Why didn’t you tell him about the meeting? ( 2006四川，35) — He rushed out of the room _________ I could say a word. A. before B. until C. when D. after 【解析】选A。本题考查连词before表示“还没来得及……就……”的用法。句意为：我还没来得及说一句话，他就冲出了房间。 4. 表示“以免，以防，趁……还没有……”，强调动作的必要性，以避免或防止从句动作的发生。 He made a mistake, but then he corrected the situation _____ it got worse.（2003北京） A. until B. when C. before D. as 【解析】选C。由made a mistake和转折词but可知本题句意是“他犯了一个错误，但在事情进一步恶化之前他改变了形势。”故答案正确答案为C项。
after，before，since用法区别 1.after的用法小结 1. 用作介词，与一段时间连用表示“在…之后”时，注意它与in的区别：after表示以过去时间为起点的一段时间以后，且通常与过去时态连用；而in则表示以现在为起点的一段时间以后： He came backafter two days. 他两天后就回来了。 He will come back in twodays. 他过两天就回来。 但after 若是与一点时间连用，则可与过去时态也可与将来时态连用： H e came back after 4 o’clock. 他是四点钟以后回来的。 He will come back after next month. 他将在下个月以后回来。 2. 用作连词引导时间状语从句时注意：若主句用将来时态(或含有将来意味)，则时间状语从句要用一般现在时态(表将来意义)，而不能直接使用将来时态：他回来后我就走。 正：I’ll leave after he comes back. 误：I’ll leave after he will come back. 3. 用作副词，表示“后来”、“ (一段时间)以后”，通常放在表示时间的副词之后：soon after 不久以后 two days after 两天后 4. 用于习语after all 终究，毕竟： I was right after all. 毕竟我是对的。 After all, he’s only six years old. 毕竟，他才六岁。 2.Before的用法小结 高三课本第十五单元，INTER GATING SKILLS 和WORKBOOK READING部分有如下的句子： ⒈The shop was successful，but it was about sixty years before people started to buy jeans for fashion as well as for work. ⒉However，it probably will not be long before the other mountainous areas of China such as Sichuan，Xinjiang and Yunnan are developed，and as more facilities become available，prices will almost certainly fall. 其中涉及到before的用法，下面就其用法进行总结。 一、可以用作介词 ⒈)指时间上早于，在……之前，如： She has lived here since before the war. 她从战前就一直在这儿住。 ⒉)指位置在前面，如：
before和ago的区别 before和ago都能表示在一段时间以前，但是二者的内涵和具体用法有明显的区别： 1. before表示从过去或将来某一时间算起多少时间以前，由于与这一时间状语连用的行为先发生在过去或将来某一时刻之前，因此往往出现在过去完成时态或将来完成时态中。例如： ①I called him up last night，but his mother told me he had left for Wuhan two days before. ②She said that she had married him five years before. 2.如果不具体表明多少时间以前，before意为"从前；以前"，表示从现在开始追溯到过去一段时间，或者主句的谓语动词表示的是经常、反复发生的行为，以副词的形式置于句末，可以用在现在完成时态中。例如： ①I have never been to Beijing before. ②Have you ever seen a tiger before?
③I often go over the lessons that I have learned a few days before. 注意：before前的时间状语如果是特定的，含义不一样。试比较： He said he had arrived here a day before. (一天前) He said he had arrived here the day before. (前一天) 3. ago指的是从现在起到过去时间的某一点的一段时间。这个时间状语常与一般过去时态或过去进行时态连用。例如： ①I graduated from the college twenty years ago. ②I was asked what I was doing a month ago. 4. 表示在某一时间点或事件以前时，只能用before，不用ago。因为这种用法是将before当作介词或连词使用。ago不具有这种功能。例如：
with[wIT] prep.1.与…(在)一起，带着：Come with me. 跟我一起来吧。/ I went on holiday with my friend. 我跟我朋友一起去度假。/ Do you want to walk home with me? 你愿意和我一道走回家吗 2.(表带有或拥有)有…的，持有，随身带着：I have no money with me. 我没有带钱。/ He is a man with a hot temper. 他是一个脾气暴躁的人。/ We bought a house with a garden. 我们买了一座带花园的房子。/ China is a very large country with a long history. 中国是一个具有历史悠久的大国。3.(表方式、手段或工具)以，用：He caught the ball with his left hand. 他用左手接球。/ She wrote the letter with a pencil. 她用铅笔写那封信。4.(表材料或内容)以，用：Fill the glass with wine. 把杯子装满酒。/ The road is paved with stones. 这条路用石头铺砌。5.(表状态)在…的情况下，…地：He can read French with ease. 他能轻易地读法文。/ I finished my homework though with difficulty. 虽然有困难，我还是做完了功课。6.(表让步)尽管，虽然：With all his money, he is unhappy. 尽管他有钱，他并不快乐。/ With all his efforts, he lost the match. 虽然尽了全力，他还是输了那场比赛。7.(表条件)若是，如果：With your permission, I’ll go. 如蒙你同意我就去。8.(表原因或理由)因为，由于：He is tired with work. 他工作做累了。/ At the news we all jumped with joy. 听到这消息我们都高兴得跳了起来。9.(表时间)当…的时候，在…之后：With that remark, he left. 他说了那话就离开了。/ With daylight I hurried there to see what had happened. 天一亮我就去那儿看发生了什么事。10. (表同时或随同)与…一起，随着：The girl seemed to be growing prettier with each day. 那女孩好像长得一天比一天漂亮。11.(表伴随或附带情况)同时：I slept with the window open. 我开着窗户睡觉。/ Don’t speak with your mouth full. 不要满嘴巴食物说话。12.赞成，同意：I am with you there. 在那点上我同你意见一致。13.由…照看，交…管理，把…放在某处：I left a message for you with your secretary. 我给你留了个信儿交给你的秘书了。/ The keys are with reception. 钥匙放在接待处。14 (表连同或包含)连用，包含：The meal with wine came to ￡8 each. 那顿饭连酒每人8英镑。/ With preparation and marking a teacher works 12 hours a day. 一位老师连备课带批改作业每天工作12小时。15. (表对象或关系)对，关于，就…而言，对…来说：He is pleased with his new house. 他对他的新房子很满意。/ The teacher was very angry with him. 老师对他很生气。/ It’s the same with us students. 我们学生也是这样。16.(表对立或敌对)跟，以…为对手：The dog was fighting with the cat. 狗在同猫打架。/ He’s always arguing with his brother. 他老是跟他弟弟争论。17.(在祈使句中与副词连用)：Away with him! 带他走！/ Off with your clothes! 脱掉衣服！/ Down with your money! 交出钱来！ 【用法】1.表示方式、手段或工具等时(=以，用)，注意不要受汉语意思的影响而用错搭配，如“用英语”习惯上用in English，而不是with English。2.与某些抽象名词连用时，其作用相当于一个副词：with care=carefully 认真地/ with kindness=kindly 亲切地/ with joy=joyfully 高兴地/ with anger=angrily 生气地/ with sorrow=sorrowfully 悲伤地/ with ease=easily 容易地/ with delight=delightedly 高兴地/ with great fluency =very fluently 很流利地3.表示条件时，根据情况可与虚拟语气连用：With more money I would be able to buy it. 要是钱多一点，我就买得起了。/ With better equipment, we could have finished the job even sooner. 要是设备好些，我们完成这项工作还要快些。4.比较with 和as：两者均可表示“随着”，但前者是介词，后者是连词：He will improve as he grows older. 随着年龄的增长，他会进步的。/ People’s ideas change with the change of the times. 时代变了，人们的观念也会变化。5.介词with和to 均可表示“对”，但各自的搭配不同，注意不要受汉语意思的影响而用错，如在kind, polite, rude, good, married等形容词后通常不接介词with而接to。6.复合结构“with+宾语+宾语补足语”是一个很有用的结构，它在句中主要用作状语，表示伴随、原因、时间、条件、方式等；其中的宾语补足语可以是名词、形容词、副词、现在分词、过去分词、不定式、介词短语等：I went out with the windows open. 我外出时没有关窗户。/ He stood before his teacher with his head down. 他低着头站在老师面前。/ He was lying on the bed with all his clothes on. 他和衣躺在床上。/ He died with his daughter yet a schoolgirl. 他去世时，女儿还是个小学生。/ The old man sat there with a basket beside her. 老人坐在那儿，身边放着一个篮子。/ He fell asleep with the lamp burning. 他没熄灯就睡着了。/ He sat there with his eyes closed. 他闭目坐在那儿。/ I can’t go out with all these clothes to wash. 要洗这些衣服，我无法出去了。这类结构也常用于名词后作定语：The boy with nothing on is her son. 没穿衣服的这个男孩子是她儿子。 （摘自《英语常用词多用途词典》金盾出版社） - 1 -