4)当because引导的从句与否定的主句连用,而主句又位于句首时，之前不用逗号,因为主句动词否定的是其后的全部内容。为了突出 because从句,because 前常加上副词,如：just,only,simply,chiefly等;在这种情况下,常常会形成否定的转移。如果是在口语中,在because前要有一个停顿(逗号),才能表示出否定没有转到 because从句中.如：

　　You should not despise a man just because he is poorly dressed.

　　She is not marrying Bill,because he is poor.

　　五、方式状语从句 as(以…方式), as if/ as though

　　Why is she looking at me as though she knew me? 他为什么那样看我?像是认识我似的。

　　He behaves as if he owned the house. 他的样子好像他拥有这个房子。

　　六、目的状语从句 so that, in order that ,lest, in case, for fear that

　　七、条件状语从句 if, once, as/so long as, unless

　　She doesn’t speak ____________her friend, but her written work is excellent.

　　A. as well as B. so often as

　　C. so much as D. as good as

　　He speaks English _____________he speaks his mother tongue.

　　A. so good as B. as good as

　　C. so well as D. as well as

　　You will be late ________ you leave immediately.

　　A. unless B. until

　　C. if D. or

　　八、让步状语从句 though, although, even if, even though, as(尽管) , while (虽然，而), whatever, whoever, wherever, whenever, however, whichever no matter…

　　九、比较状语从句 than

　　1.______ I accept that he is not perfect, I do actually like the person. (2004 江苏)

　　A. While B. Since

　　C. Before D. Unless

　　2.We won’t give up ______________we should fail ten times.

　　A. even if B. since

　　C. whether D. until

　　3.Allow children the space to voice their opinions, ______ they are different from your own. (2005 湖南)

　　A. until B. even if

　　C. unless D. as though

　　4.If we work with a strong will, we can overcome any difficulty, ______________great it is.

　　A. what B. how

　　C. however D. whatever

　　5.________, Mother will wait for him to have dinner together.

　　A. However late is he

　　B. However he is late

　　C. However is he late

　　D. However late he is

　　though, although

　　Smart though he is ,he can make stupid mistakes sometimes.

　　Driver though he is, he sings like a pop-star.

　　Though/although exhausted, he kept on working till midnight.

　　as

　　______, he can never solve the problem alone.

　　A. Clever and intelligent he is

　　B. Clever and intelligent as he is

　　C. As he is clever and intelligent

　　D. As clever and intelligent he is