初三英语上册知识点：语法时态
语法：直接引语变间接引语。直接引用别人的话叫直接引语，用来转述别人的话叫间接引语。例：
He said, "He will go to Beijing tomorrow." （直接引语）
He said that he would go to Beijing the next day.
直接引语变间接引语时时态、人称及一些时间或个别词都要做相应的改变。
①时态：
一般现在时→一般过去时 一般将来时→过去将来时
现在进行时→过去进行时 一般过去时→过去完成时
现在完成时→过去完成时
* 但真理性的句子时态不变。例：
He said: "The sun rises in the east."
He said that the sun rises in the east.
他说太阳从东方升起。
②时间：
now→then, last month→the month before.
today→ that day, three days ago→three days before.
tonight→that night, tomorrow→the next day.
yesterday→the day before, the day after tomorrow→in two days.
③其它变化：
this→that these→those here→there
come→go
句式的改变：
①直接引语是陈述句加"that"可以省去。例：
He said, "My sister was here three days ago."→
He said that his sister had been there three days before.
②直接引语是一般疑问句，变成用if/whether引导的宾语从句，人称时态等作相应改变。
Mother asked me, "Did you buy any meat for lunch?"→
Mother asked me if/whether I had bought some meat for lunch.
③直接引语是特殊问句，变成由原来疑问词一样的连接词引导的宾语从句，时态人称等作相应改变。例：
"What do you do?" he asked me.
He asked me what I did.
④直接引语是选择问句变成由whether或if引导的宾语从句。
"Do you like English or Chinese?" He asked me.
He asked me whether I liked English or Chinese.
语法：被动语态
1．英语中动词有两种语态：主动语态和被动语态
主动语态表示主语是谓语动词动作的执行者，被动语态表示主语是谓语动词动作的承受者。
当我们强调谁是某个动作的执行者，即"谁做了某种事情"时，用主动语态。
eg: Daniel bought a new computer 丹尼尔买了一台新电脑。（不是别人）
如果主语不是动作的执行者，而是动作的承受者时，就是被动语态。
eg: A new computer was bought by Daniel 一台新电脑被丹尼尔买了。
被动语态的谓语由be + 动词的过去分词构成，其中be是助动词，随时态改变。
一般现在时的被动语态由"am / is / are ＋动词的过去分词"构成。
一般过去时的被动语态由"was / were ＋动词的过去分词"构成。
2．被动语态的用法：
当不知道或没必要说明动作的执行者时，用被动语态。
eg:Rice is grown in South China. 华南种植水稻。（没必要说明是谁种）
This bridge was built 100 years ago.这座桥是100年前建的。（不知道谁建的）
Passive voice with 'by'
在被动语态中，如果我们也要把动作的执行者表达出来的话，我们就在被动句子的后面，用 "by+动作的执行者（宾格）"来表示。
e.g.Jack broke the window. （主动语态）
The window was broken by Jack.（被动语态）窗户是被杰克打碎的。
Meals are cooked by her mother at home.在家饭是她母亲烧的。
The book was written by him several years ago. 这本书是他几年前写的。
3．难点：
1）. 当一个含有复合宾语（宾语+宾补）的句子变为被动语态时， 只能把宾语变为被动语态的主语，宾补还放在原来的位置。
e.g.We call him Xiao Wang.---He is called Xiao Wang.
He cut his hair short.---His hair was cut short.
2）. 带双宾语的动词变为被动语态时， 常常把间接宾语变为被动语态的主语；如果直接宾语变为被动语态的主语时，间接宾语前要加介词to或 for.
e.g.Someone gave the boy an apple.-- The boy was given an apple.
An apple was given to the boy.
His mother bought a present for him.---He was bought a present.
A present was bought for him.
3）. 在let, hear, watch, see, help, have 等词的句子中，主动语态不加to, 被动语态要加 to.
e.g. The boss makes us work 12 hours a day.--- We are made to work 12 hours a day.
They heard the children sing that morning.--- The children were heard to sing that morning.
⑤直接引语是祈使句，根据说话语气变成ask/tell/order warn sb. to do sth.的结构。例：
She said to me, "Stand up."→
She asked me to stand up.
Father said to his son, "Don't play football in the street."→
Father told his son not to play football in the street.
语法：祈使句
表示命令、叮嘱等的句子叫祈使句。祈使句省略主语，以动词原形开头，常加please表示客气。常有以下三种结构：
（1）行为动词开头。例：
Sit down, please. (Please sit down.)
Come here.
Go there.
（2）系词be开头。
Be careful!
Be silent.
（3）Let开头。例：
Let's do it at once.
Let him do it.
注：（1）祈使句的否定式在句首加don't。例：
Don't speak in Chinese.别用汉语说。
Don't be here so early.别来这太早。
（2）在祈使句前可以加never或always。
Never climb up too high. It's dangerous.
Always come on time.总是准时。
Always be polite to others.总是对人礼貌。
语法：并列句
由并列连词but，and，or，so，while等构成的并列句，例：
HehelpsmeandIhelphim。
Hewasill，buthestillworkedon。
Helikescookingwhilehiswifelikestravelling。
语法：条件状语从句，以if引导。
if在英语中可以构成条件状语从句，意为“如果”，也可以构成宾语从句，意为“是否”。例：
Idon‘tknowifhewillcometomorrow。（宾从）
我不知道他明天是否来。
Ifhecomes，I’llletyouknow。（条从）
如果他来，我让你知道。
*（1）在if构成的条件状语从句中，如果主句是将来时，或祈使句或有情态动词，从句通常用一般现在时。如上面的例句，再如：
Hecanpasstheexamifhestudieshard。
如果他努力学习会通过考试的。
（2）if构成的条件从句可以放于句子前面，也可以放于后面。例：
Ifitrains，Iwon‘tgowithyou。
如果下雨我就不和你去了。
Iwon’tgowithyouifitrains。
语法：比较级和最高级。
构成：单音节词和大部分双音节词变化词本身。
例：long→longer→longest
（比较级在词尾加er，最高级在词尾＋est。）
big→bigger→biggest
easy→easier→easiest
多音节词在原形前＋more和most，构成比较级、最高级。例：
beautiful→morebeautiful→mostbeautiful
interesting→moreinteresting→mostinteresting
特殊词：good/well→better→best
much/many→more→most
ill/bad/badly→worse→worst
little→less→least
用法：两者比较用比较级，三者、三者以上用最高级。例：
Heistallerthanhisbrother。他比哥哥高。
Heisthetallestinhisfamily。他在家里最高。
△最高级要有比较范围，常用in或of短语表示。例：
Heisthefastestofthethree。
三个人中他最快。
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