题目内容
A Record-Breaking Rover
NASA&39;s Mars rover Opportunity has boldly gone where no rover has gone before-- at least in terms of distance. Since arriving on the Red Planet in 2004, Opportunity has traveled 25.01 miles, more than any other wheeled vehicle has on another world. On July 27, after years of moving about on Martian ground, the golf-cart:sized Opportunity had driven more than 24 miles, beating the previous record holder--a Soviet rover sent to the moon in 1973.
"This is so remarkable considering Opportunity was intended to drive about 1 kilometer and was never designed for distance," says John Callas, the Mars Exploration Rover Project Manager.
He works at NASA&39;s Jet Propulsion Laboratory in Pasadena, California. "But what is really important is not how many miles the rover has racked up, but how much exploration and discovery we have accomplished over that distance."
Opportunity
The solar-powered Opportunity and its twin rover, Spirit, landed on Mars I0 years ago on a mission expected to last 3 months. The objective of the rovers was to help scientists learn more about the planet and to search for signs of life, such as the possible presence of water.
Spirit stopped communicating with Earth in March 2010, a few months after it got stuck in a sand pit. But Opportunity has continued to collect and analyze Martian soil and rocks.
During its mission, Opportunity has captured, and sent back to Earth, some 187,000 panoramic and microscopic images of Mars with its cameras. It has also provided scientists with data on the planet&39;s atmosphere, soil, rocks, and terrain.
Marathon Rover The rover doesn&39;t seem to be ready to stop just yet. If Opportunity can continue on, it will reach another major investigation site when its odometer hits 26.2 miles. Scientists call this site Marathon Valley, because when the rover reaches the area, it will have traveled the same distance as the length of a marathon since its arrival on Mars.
Researchers believe that clay minerals exposed near Marathon Valley could hold clues to Mars&39;s ancient environment. Opportunity&39;s continuing travels will also help researchers as they plan for an eventual human mission to the Red Planet.
Opportunity is a record-breaking rover in the sense of __________. 查看材料
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2012年我国夏粮生产获得了较好收成。全国夏粮总产量达到12995万吨，比201 1年增加356万吨，增长2．8％，超过l997年12768万吨的历史最高水平，比10年前增长31．6％。2012年，河北、山西、江苏、安徽、山东、河南、湖北、四川、陕西、甘肃、新疆这11个主产省(区)增产夏粮364万吨，其中安徽增产80万吨、山东增产75万吨、河北增产63万吨、河南增产55万吨．在非主产省(市、区)中北京、辽宁、浙江、湖南、重庆、云南、宁夏有不同程度减产。
2007～2012年全国夏粮产量
2012年11个主产省(区)夏粮播种面积及总产量
2002年全国夏粮产量约为：
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发件人：李林
收件人：林伟
日 期：2006年12月15日，星期日，9:30
内 容：打算去英国剑桥大学学习，想了解中国学生在英国学习的情况。
To:
From:
Date:
Subject:
Dear Lin Wei,
premises. Your Managing Director is interested in Waterside Industrial Park, and has asked you to write a letter to find out more information.
&8226;Read Waterside Industrial Park's advertisement below, on which your Managing Director has already made some notes.
&8226;Then, using all your Managing Director's handwritten notes, write your letter to Rosemary Brown at Waterside Industrial Park.
&8226;Do not include postal addresses.
&8226;Write 120-140 words on a separate sheet.
在现有的价格水平下，总需求增长超过经济潜在的产出能力（AD＞AS)，就会发生（)的通货膨胀。
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