观察到了一条淡淡的光亮路径，指出有东西在相关的恒星后面移动，其他观察者也证实了这一发现，所以第二段主要讲述了该行星是如何被发现的，故选B项。

　　3．What magazine might this passage be taken from?

　　A．Astronomy． B．Industry．

　　C．Spaceflight． D．Agriculture.

　　解析　A　文章出处题。根据全文可知，本文主要介绍了目前在太阳系新发现的一颗疑似小行星的天体，这类文章最可能出自与天文学相关的杂志上，故选A项。

　　B

课标话题 人与自然·宇宙奥秘探索 体裁 记叙文 词 数 328 难度 　　(2019·长沙一中开学检测)A new study suggests that dark markings on the planet Mars represent sand-not water. The research in 2015 suggested that lines on some Martian hills were evidence of water. Yet American scientists now say these lines appear more like dry, flows of sand. If water is present, it is likely to be a small amount. Water in liquid form would be necessary for microbial(微生物的) life.

　　NASA, the American space agency, said more research is needed. Michael Meyer is the lead scientist for NASA's Mars exploration programme. He noted that the latest study does not reject the presence of water. But he admitted, "It just may not be as exciting as the idea of rivers going down the sides of cliffs(悬崖)．"

　　The new findings come from a team led by Colin Dundas of the United States Geological Survey. His team measured 151 of these lines in 10 areas. Most of the lines end with slopes between 28 degrees and 35 degrees. These measurements are similar to active sand dunes(沙丘) on both Mars and Earth. A small covering of dust that moves and sometimes becomes lighter might help explain the markings. They usually appear in the Martian summertime, and then disappear until the next year. If these lines are dry, this suggests that recent Mars has not had large volumes of liquid water. Dundas and his research team say that many questions remain.

　　"I still think that Mars has a great potential for having had life early on in its history，" Meyer said. "As long as that's true, we also have a reasonable possibility of life still being on Mars. It just happens to be cryptic or well hidden."

　　NASA currently has no robotic vehicle-either on Mars or in development-with the ability to climb steep slopes. The lack of such equipment has engineers coming up with ideas like Martian helicopters or planes without pilots.

语篇导读　本文主要讲述了美国科学家的一项新的研究发现：火星上黑色的标记是沙