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.
and whether, presuming such life forms having left fossil traces to begin with, those traces can
and whether, if it is presumed that such life forms left some fossil traces to begin with, can those traces
and whether, presuming such life forms left fossil traces to begin with, those traces
and, presuming such life forms did leave some fossil traces to begin with, if they can
and, presuming such life forms to have left fossil traces to begin with, if they
Answer: A
我觉得在A里如果完成时(having left) 是做定语修饰lift forms 的话,好像不大对,不是白勇语法上说说过完成时不能做定语修饰的吗。