四六级考试

【单选题】{{B}}Passage OneQuestions 26 to 29 are based on the passage you have just hearD、{{/B}}
A、Its chemical elements must be studieD、
B．Its temperature must be lowereD、
C．Big spaceships must be built.
D．Its atmosphere must be changeD、

网考网参考答案：D
网考网解析：
[听力原文] What is one of the things that must be done before man can live on Mars [解析] 文中提到了几个火星不适合人类居住的因素，由其中的lf the atmosphere were like that of the earth，this might be possible．But in fact it is mostly carbon dioxide可推知，[D]“改善大气环境”是人类移居火星之前必须解决的问题之一。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>