火星的样子: pink sky, orange sunset, vast desert, massivecanyon, red planet 与气候有关的词: climate,blazing hot, freezing cold 常见化学物质: iron,carbon dioxide,nitrogen,oxygen物质的三态:solid,fluid,gas as a result 结果 remind sb.of sth.提醒某人某事 paya visit进行访问 upside down 倒置地;颠倒的 be used to doing sth.习惯于做某事 be home to...是.....的所在地 现在完成进行时的用法，例如: For the past 50 years,scientistshave been doing just that...except that spacecraft, not humans.have been making the trip. 并列结构作主语时主谓一致，例如: Mars,along with Mercury,hasthe lowest surface gravity in the solar system. if引导的条件状语从句，例如: ifthat's true,then realMartians arejust like creatures that are all around us here on Earth.