第6部分：完形填空

　　阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。

Solar Storm

　　At the end of October 2003, a sudden solar storm hit the earth. A solar storm refers to the large amounts of charged particles released into space ＿＿＿＿＿（51） the solar energy increases. The release of the energy ＿＿＿＿＿ （52） place along with the activity of the sunspots with a cycle of 11 years. This time, the ＿＿＿＿＿ （53） of the storm exceeded expectations.

　　This ＿＿＿＿＿（54） of intense solar storm was caused by the eruption of a solar flare （闪光） and the ejection （喷发） of the solar corona （日冠） on October 28, 2003. Large amounts of charged particles moved 150,000,000 kilometers through space toward the ＿＿＿＿＿（55） in 19 hours. They could affect aircraft roaming （漫游） in space.

　　The high-energy particles will ＿＿＿＿＿（56） some of the parts of an aircraft. The~ may also cause it to fail. High-energy particles can threaten the safety of an aircraft at a high orbit. If an aircraft orbits at a lower orbit, it is ＿＿＿＿＿（57） because it is under the protection of the earth's magnetic field.

　　A solar storm not only affects aircraft but also is a ＿＿＿＿＿（58） to the environment and humans. The aerosphere and magnetic field of the earth can ＿＿＿＿＿（59） humans from ultraviolet radiation and X-rays. While most of the X-rays are absorbed after they enter the aerosphere （大气层）, still a few can ＿＿＿＿＿（60） the ground.

　　The geomagnetic storm caused by this round of solar storm reaches its highest level on the two ＿＿＿＿＿（61） of the earth, which affects electricity supply of North America. Overexposure to ＿＿＿＿＿（62） threatens the health of passengers on planes flying over the Polar Regions. If we fly in the sky during such a solar storm, it ＿＿＿＿＿（63） we receive ten times the X-ray radiation. It's really damaging.

　　Scientists say a solar eruption is like the sun sneezing, which will make the earth ＿＿＿＿＿（64） a cold. Though this natural force is irresistible, scientists can still ＿＿＿＿＿（65） its movement accurately by monitoring. Facing successive solar storms, humans can't drop their guard.

　　51 A since B when C until D though

　　52 A finds B adjusts C holds D takes

　　53 A intensity B height C width D density

　　54 A piece B part C round D set

　　55 A star B earth C moon D sun

　　56 A dominate B develop C damage D descend

　　57 A safe B dangerous C comfortable D manageable

　　58 A limit B cause C force D threat

　　59 A separate B benefit C distinguish D protect

　　60 A lose B reach C break D prepare

　　61 A poles B mountains C rivers D lakes

　　62 A light B storm C radiation D pressure

　　63 A recommends B means C proposes D advises

　　64 A turn B stop C become D catch

　　65 A detect B start C experience D change

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