Arewehumansaloneinspace？Scientistshavebeenworkingonthis...
问题详情：Arewehumansaloneinspace？Scientistshavebeenworkingonthisquestionforalongtime．Andrecently，newdiscoveriesoffermorehopethatsomeformoflifeexistedonMarsinthepast，andperhapsisstillthereatpresent．According...