英语专四语法解析：原因状语从句
英语专四语法是专四考生们复习时的基础环节，考题的形式虽然是20道语言知识题但是对于专四考试各题型来说都会考察到，下面是英语专四语法解析，希望能系统的帮助大家复习英语专四语法。
引导原因状语从句的从属连词有because(因为), as(由于), since(既然), now(that)(既然), when(既然), seeing (that) (由于，鉴于), considering (that)(考虑到), given (that) (考虑到)等。
一、引导原因状语从句的从属连词主要的有because,for,in that,for the reason that;as,seeing (that), seeing as;since;now (that); considering (that)等：The woolly shrank because it was washed badly. 毛衣因为洗涤的方法不好而缩水。I can’t get to sleep because of the noise outside. 由于外面声音嘈杂我睡不着。Since [As] we’ve no money, we can’t buy it. 由于我们没钱，我们不能购买它。Seeing that it’s raining, we’d better stay indoors. 既然外边在下雨，我们最好待在室内。Now that you are here, you’d better stay. 你既然来了，最好还是留下吧(既来之，则安之)。【注】除以上提到的大家比较熟悉的引导原因状语从句的从属连词外，when有时也可引导原因状语从句(when表示“既然”)I won’t tell you when you won’t listen. 既然你不想听，那我就不告诉你了。
二、关于not…because结构该结构中的否定词有时否定主句，有时否定从句，一般要根据句子的意思作出正确或合乎逻辑的理解。若not否定主句，最好在because之前用逗号，否则会引起歧义，如下句在没有特定上下文时就有两种解释：I didn’t go because I was afraid. 我没有去是因为怕。/ 我不是因为怕才去的。不过若because之前有just修饰，一般认为not 是否定从句的：You shouldn’t get angry just because some people speak ill of you. 你不要因为有人说你坏话而生气。
三、because不能与so连用汉语习惯上说“因为…所以…”，但英语习惯上却不能将 so与because 连用：因为下雨，所以我们得呆在家里。正：Because it was raining, we stayed at home. / It was raining, so we stayed at home.误：Because it was raining, so we stayed at home.
四、because从句与 because of短语的转换Because引导的原因状语从句有时可与because of 短语转换，because of后加的原因可以为好或坏但最正规的还是because He can’t come because he is ill. / He can’t come because of his illness. 他因病不能来。I said nothing about it because his wife was there. / I said nothing about it because of his wife’s being there. 因为他妻子在那儿，我对此事只字未提。比较：because, since, as和for1) because语势最强，表示不知道的原因用because，即说话人认为听话人不知道。因此because从句是全句最重要的部分，通常被放置于主语之后。 当原因是显而易见的或已为人们所知，就用as或 since。I didn't go, because I was afraid.Since /As the weather is so bad, we have to delay our journey.2) for虽然表示原因，但因语气比because弱得多，是可说可不说的话，只能位于主句之后。这时，for是并列连词，如果不是因果关系，而是对前面主语内容加以解释或推断时，只能用for。He is absent today, because / for he is ill.He must be ill, for he is absent today.
英语专四语法解析：时间状语从句
§引导词有：when, whenever, after, as, while, since, before, until, as soon as, now that, once, directly等。
____ to sleep than the telephone rang once more.
A) Hardly he had gone
§B) No sooner had he gone
C) Not until he went
D) Scarcely did he go
Hardly /Scarcely… when 和 No sooner… than
She comes to me whenever she feels lonely.
Once you object to a man, everything he does is wrong.
Now (that) you mention it, I do remember.
Directly he was out of sight of her, he wanted to see her.
I didn’t wait a moment, but came immediately you called.
The minute/ moment/ day, the first/ second/last time, each/every/next time 都可引导时间状语从句。
The day he returned home, his father was already dead.
英语专四语法解析：方式状语从句
方式状语从句通常由as,as if, as though，the way, what引导;
eg：Always do to the others as you would be done by.
When enter Rome do as the Romans do .
(1)as从句带有比喻的含义，意思是正如…，就像;
(2)as if/though：仿佛……似的，好像……似的;
有时用虚拟语气，有时不用;
eg：They completely ignore these facts as if (as though) they never existed. (与事实相反，谓语用虚拟语气。)
He looks as if (as though) he had been hit by lighting.
(与事实相反，谓语用虚拟语气。)
It looks as if the weather may pick up very soon.
(实现的可能性较大，谓语用陈述语气。)
(3)the way：可以连接两个句子，表达就像……一样;
eg：I should do the job the way my father did.
Many Europeans now apparently view the US. the way many Americans view Mexican as a cheap place to vacation, shop and party.
(4)what：就像，犹如;
eg：Air is to man what/as water is to fish.
句型：A is to B what C is to D.
eg：A1 Gore calls global warming an inconvenient truth, as if merely recognizing it could put us on a path to a solution.
put sb. on a path to a solution：找到解决的办法：
英语专四语法解析：定语从句
定语从句可以分为限定性定语从句(紧跟先行词，与先行词之间不用逗号隔开)和非限定性定语从句(与先行词或主句间有逗号隔开，修饰先行词、整个主句或主句的一部分，仅起补充说明作用，若去掉，主句意思依然完整)。定语从句的常见考点有：
·定语从句和同位语从句的区别：两者的区别在于定语从句的关系词在从句中充当一个成分，而同位语从句的连接词在从句中不充当成分。例如：
The news that we heard is not true.(定语从句)
The news that he won the prize is not true.(同位语从句)
·定语从句与状语从句的区别：两者的区别在于定语从句是修饰其先行词的，而状语从句是修饰主句的谓语动词或整个主句，在主句中充当状语。例如：
He found the books where he had put them.(状语从句)
He found the books in the place where he had put them.(定语从句)
·定语从句与强调句的区别：区别两者的方法是强调句去掉It is/was...that...后仍然是一个语法结构和语义都完整的句子，而定语从句在去掉It is/was和从句的关系词后句子结构不完整。例如：
It is the place where they lived before.(定语从句)
It is in the place that they lived before.(强调句)
·定语从句中的先行词：先行词是定语从句中关系词前面的名词。定语从句一定要有先行词。例如：
Is this book the one that you bought yesterday?(先行词为the one)
Is this the book that you bought yesterday?(先行词为the book)
·定语从句中关系代词与先行词的一致性：定语从句的谓语动词和先行词保持主谓一致;当先行词为one of+名词复数时，定语从句的谓语动词要用复数;当先行词为the only one of+名词复数时，定语从句的谓语动词要用单数。例如：
He is the only one of the students who was here just now.
He is one of the students who were here just now.
·定语从句的关系词：关系词指引导定语从句的关联词，包括关系代词和关系副词。
a)that指物，有时也可以指人;which指物，不能指人。只能用that而不能用which的情况有：
先行词前有形容词最高级或序数词修饰时;
先行词前有next,last,very,any,little,no等修饰时;
先行词是all,much,little,none等时;
先行词是不定代词something,anything,nothing,everything时。
b)先行词是人+物时，关系词要用that而不用which/who。例如：
He talked about some writers and books that were unknown to us all.
(正)
He talked about some writers and books which/who were unknown to us all.(误)
c)先行词本身是that时，一般用which引导定语从句。例如：
The predicate is that which is said of the subject.
d)在who开头的疑问句中，若要用关系代词引导定语从句，则用that。例如：
Who is the girl that is singing in the hall?
e)当关系词后面有插入语时，用which引导定语从句。例如：
Here is the English grammar book which,as I have told you,will help to improve your English.
f)which可以引导非限定性定语从句，也可以放在介词后面，that则不能。例如：
The room in which she lives is a large one.
g)as引导定语从句，可以指代整个主句，位置可以在主句前，也可以在主句后。which指代整个主句，只能放在主句后。例如：
As might be expected,the response to the question was very mixed.
The response to the question was very mixed,as/which might be expected.
英语专四语法解析：同位语从句
接同位语从句的词有：answer, belief, concept, decision, discovery, problem, promise, statement, probability 等。
同位语从句多由that 引导，疑问代词who, which, what 和疑问副词where, when, how, why 也可以。
The news that he has won the game is exciting.
It is the question where we should have dinner.
一、定义
一个名词或代词后面有时跟一个名词或起名词作用的成分，对前者进一步说明，叫做同位语。在某些抽象名词后可以用that, whether, when等引导的从句作同位语，称为同位语从句。这些名词有：
agreement一致意见assumption假定awareness意识
belief看法conclusion结论conviction深信
decision决定delusion错觉determination决心
discovery发现doubt怀疑dream梦想
evidence证据explanation解释fact事实
feeling感觉guarantee保证guess猜测
hope希望idea观点knowledge认识
likelihood可能性message信息mind想法
news消息notion观念objection反对
opinion观点possibility可能性prediction预测
probability可能性problem问题proof证据
proposal建议proposition论点、主张question问题
realization认识rumor传闻sign迹象
truth事实theory理论thought想法
二、结构
(一)由that引导
I have no doubt that he will overcome all this difficulties.
他会克服一切困难，对此我并不感到怀疑。
【特别提示】：同位语从句引导词that不可省略。
(二)由whether引导
·The question whether we need more time to do the work has not been decided.
我们是否需要更多时间来做这项工作，这个问题还未决定。
(三)由其他词引导的同位语从句
·I have not made up my mind what elective subjects I am to take next term.
我还没有决定好下学期上哪些选修课。
·When you are about halfway through the story, try to make a guess how the plot will develop.
当你把故事读到一半时，猜测一下情节将如何发展。
·I have no idea when I will be back from Shanghai.
我不知道我什么时候从上海回来。
(四) 同位语从句与被修饰名词的分割
有时，为了保持句式的平衡，将同谓语从句与被修饰的名词分割，其间出现其他成分。
·Concerns were raised that witnesses might be encouraged to exaggerate their stories in court to ensure guilty verdicts.
人们日益担心，证人可能会因此而受到鼓励，在法庭上夸大事实以保证陪审团对被告做出有罪的判决。(这里先行词concerns与that同位语从句被谓语were raised隔开。)
三、翻译方法
同位语从句有以下五种翻译方法：
①可以直接翻译在所修饰词后面。
②放在所修饰的名词前面，充当定语。
③译成独立句子：先翻译主句，然后用“就是……”或者“即……”引导出同位语从句，或者把同位语从句译成独立的句子，由冒号或破折号引出。
④用代词指代：先把同位语从句中的内容翻译出来，在后面用“这”或“那”等代词复指它，参加句子主体的构成。
⑤译成宾语 ：把同位语从句修饰的名词转译成动词，而把同位语从句译成宾语。
【真题例句】
What is harder to establish is whether the productivity revolution that businessmen assume they are presiding over is for real.
【解析】
句子可拆分为：What is harder to establish is //whether the productivity revolution //that businessmen assume //they are presiding over// is for real.
主句为What is harder to establish is whether the productivity revolution is for real。主句包含两个从句成分：从句what is harder to establish做主语;whether the productivity revolution is for real作表语;that they are presiding over为定语从句修饰the productivity revolution;此定语从句中businessmen assume为主谓结构的插入语。以what, whatever, whoever, whether, when, where, how, why等词引导的主语从句及表语从句在翻译的时候，一般可以按照英语原文顺序来翻译。