让步状语从句
1） though, although, even if/ though引导的让步状语从句
Although he is a socialist, Mr. Wells is scarcely in sympathy with the working class尽管威尔斯先生是一个社会主义者, 但是他对工人阶级几乎毫不同情。
a. as引导的让步状语从句必须倒装, 如果动词或现在分词提前放在句首, 谓语加助动词do/does/did,will等，如：
Fail as he did. he would never give u尽管失败了,但他从未放弃。
b.做表语用的单数可数名词放在句首时，该名词前不可加冠词，如：
Child as he is, he knows much about the society.他虽然是个孩子,但对社会却很了解
c.as从句的主语是代词时,主谓无需倒装;如果主语是名词,则要倒装,如：
Diffcult as it was, they finished it in time.尽管很难,他们还是按时完成了。
Difficult as was the work, they finished it in time.尽管选项工作很难,他们还是按时完成了。
3) while引导的让步状语从句
while表示"尽管,虽然"时,可以引导让步状语从句,这时 while表达并列的转折,即主句与从句间的动作是在同一时间发生的。while引导的从句通常放在主句之前,例如：
While I felt sympathy for her, I could not do much to help.尽管我很同情她,但是我却帮不上什么忙
4) no matter how与 however引导的让步状语从句
no matter与疑问词 what, when, where, how等连用,或上述疑问词加ever,都可以引导让步状语从句,两者基本可以互换，如：
No matter how/ However sly a fox may be, it is no match for a good hunter狐狸再狡猾也敌不过好猎手
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