TT-GWD 2-34 现在分词逻辑主语

TT-GWD 2-34

A.      and whether, presuming such life forms having left fossil traces to begin with, those traces can

B.       and whether, if it is presumed that such life forms left some fossil traces to begin with, can those traces

C.      and whether, presuming such life forms left fossil traces to begin with, those traces

D.      and, presuming such life forms did leave some fossil traces to begin with, if they can      

E.       and, presuming such life forms to have left fossil traces to begin with, if they

选C 但C中的现在分词presuming逻辑主语是谁？

thanks,

 approach能presume吗？

songlovegt thanks!

结构能理解。

可是还是翻不来这句句子。求大家帮忙。

为什么B不行呢？是因为can不能提前的原因吗？

以下是引用jaylee001在2009-2-17 12:49:00的发言：

thanks,

 approach能presume吗？

我觉得不能，但是在英文语法中，有一类分词叫做“无关联分词”，它们可以没有逻辑主语，比如一些固定搭配：

Generally speaking, I'm inclined to agree with you. 
    

Supposing that there is no pure water; what shall we drink? 
    

等等，我觉得presuming在这个句子中的作用应该是属于无关联分词的用法。