小题1:C小题2:D小题3:D小题4:A 试题分析:本文叙述了美国对于太空探险的计划,一是为了保护地球,二是完成美国的火星使命。三是更进一步探险太空。让地球可以成为人们居住的地方。小题1:细节理解题。根据NASA began planning for the first moon landing since 1972 when George Bush, the US president, announced his new plan for space exploration four years ago.第一次宣布时的时间是1968年,故选C。小题2:细节理解题。根据announcing great plans for a base for humans to live on the surface of the moon forever.和The plan for the moon base, however, is the first detailed explanation of how NASA intends to prepare for the first manned exploration of deep space and a possible Mars mission within 30 years.只有选项D没有提到,故选D。小题3:细节理解题。根据teams of astronauts living there for six months at a time would mine for hydrogen and oxygen to make water and possibly rocket fuel.故选D。小题4:主旨大意题。根据本文主要谈论的是美国对于太空探险是计划,故选A。点评:做此类题目时,首先要搞清是问某一段还是全文的大意,可利用文中主要信息来把握文脉,进行综合归纳,概括文章的主题。如有标题,标题中的蕴含的信息往往是关键信息。另外,任何一篇文章都是围绕某个主题展开的,因此,许多文章中最明显的特点之一是有一个反复出现的中心词,即高频词,也叫做主题词。抓住了它,便容易抓住文章的中心。