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
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
正確答案是C，我選D，我覺得C有兩個whether似乎有重複的感覺 所以沒選
可是答案卻是C?