NASA's methodical approach to the exploration of Mars has not yet answered the questions of whether biological life forms ever emerged on Mars and whether, presuming such life forms having left fossil traces to begin with, those traces can still exist in some moist recesses of the cold and arid planet.
NASA’s methodical approach to the exploration of Mars has not yet answered the questions of whether biological life forms ever emerged on Mars and whether, presuming such life forms having left fossil traces to begin with, those traces can still exist in some moist recesses of the cold and arid planet.
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 可以少that?
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
请教一下c 的结构？我觉得c也不对，因为 presuming such life forms left fossil traces to begin with 中，preseming后面少了that。。。。。
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发表于 2010-8-29 01:26:07
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