个人vote for C,总结一下 A.最大的争议点就是can应否保留的问题,这里肯定是只涉及逻辑而非语法。句意:NASA的系统的探索火星的方法目前还没有回答...的问题。既然是探索火星,那么回答的问题就是traces是否仍然保留,而不是能否保留的问题(这是科学理论上回答的吧= =);第二前半句也没有用情态动词。第二个争议点就是having的问题:①persuming这种大家都知道的词语是不需要情态动词的,就像supposing...一样;②根据朗文,persume没有加doing的范例,就是说A中persume是加名词life forms,大家都知道having left是不能当后置定语的,固A无论从什么角度都是错的 B.if it is presumed that错,一对比presuming就有差距了,个人认为SC中正确的句子从哪个语法点都是五句中最好的= =;然后后面还有can those traces倒装,我不明白正常语序能表达的这里有什么理由会是倒装?建议大家别上新东方,赵丽老师还说最长的选项肯定是错的呢 C.presume (that),that可以省略 DE不说了
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RON’S COMMENT: the modifier "presuming" is incorrectly used in a/c/d/e, because it doesn't have a subject (i.e., if "presuming" is used in a formal sentence, then the sentence needs to mention who is making the presumption). the passive form "it is presumed" in (b) is ok -- that's the point of this kind of passive form, actually (i.e., to avoid having to mention an unimportant subject).
as stacey said, "having" in (a) is incorrect.
"to begin with" -- which is present in all five choices -- is an informal construction that isn't acceptable in formal english (unless you are literally talking about beginning some process with something; this sentence is not doing that).
(b) says "whether can..."; that's not ok.
in (d) and (e) the second "whether" is inappropriately replaced by "if".