2014年12月大学英语四级语法：从句类
导语：从句类是英语四级的语法知识点，小编收集了关于从类句的语法，供您回顾学习，希望能帮助到您!
让步状语从句
常见的连接词有though, although，as, while, even though
区分though，although，as
eg：Although/though he is a child, he can live by himself.
as 表示虽然的时候，要进行倒装;
Child as/though he is , he can live by himself.
eg：Although/though she works very hard ,she makes very little progress.
Hard as she works, she makes very little progress.
Although/though she is young, she has travelled to many countries to put shows .
Young as she is, she has travelled to many countries to put shows .
while：连接两个句子，表示虽然，但是;
eg：He is experienced while he is young.
原因状语从句
连接词：because, since, as, for ，now that, in that, owing to, due to, thanks to, because of , as a result of;
比较：because, since, as和for
1) because语势最强，用来说明人所不知的原因，回答why提出的问题。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) 由because引导的从句如果放在句末，且前面有逗 号，则可以用for来代替。但如果不是说明直接原因，而是多种情况加以推断，就只能用for。
He is absent today, because / for he is ill.
He must be ill, for he is absent today.
now that ：既然;
in that :因为，通常只能放在句中，强调重要的，唯一的.的原因;
eg：Now that this semester is finished, I am going to rest a few days and take a trip.
Human beings are different from animals in that human can speak and think.
owing to, due to, thanks to, because of , as a result of等短语后面只能接词或短语，不能接从句;
1.The anti-virus agent was not known
(直到一名医生偶然发现了它)
until a doctor find it by chance.
2.I would prefer shopping online to shopping in a department store because __________(它更加方便和省时)
it is more convenient and timesaving.
3.But since water is much cheaper than wine, and many of the fancier brands aren’t available in stores, most diners don’t notice or care.
4. While there’s no question that continuous stress is harmful, several studies suggest that challenging situations in which you’re able to rise to the occasion can be good for you.
条件状语从句：
(1)连接词：if, once, as long as, on condition that
① 如果引导的条件可以实现，主将从现;
② 如果引导的条件和事实相反，则用虚拟语气;
eg：If winter comes can spring be far behind.
As long as it doesn't rain, we can play.
You can go out on condition that you wear an overcoat.
Modern cars are far tougher to steal, as their engine management computer won't allow them to start unless they receive a unique ID code beamed out by the ignition (点火) key.
