NASA said on April 8, 2004 that its two robotic rovers would go into overtime on Mars, adding five months to their original three-month mission. The rovers, Spirit and Opportunity, have exceeded the space agency's hopes and discovered the firmest evidence yet that Mars once had warm, wet areas that could have been host to life. The landing site of the Mars Rover Spirit is seen in this mosaic taken by the rover's panoramic camera on January 18, 2004. ( JPL-Cornell-NASA/Reuters)

词汇：

NASA abbr.National Aeronautics and Space Administration（美）国家航空和宇宙航行局

rover n.流浪者，漫游者

exceed vt.超越，胜过

host vt.当主人招待

mosaic n.镶嵌图案

panoramic camera n.全景照相机