its a strange partnership,but a very effective one: satellites and space-shuttle-carried radar are helping archeologists.how?byseeingthrough sand or through treetops to locate important archeological sites.
the traditional tools of archeologists are shovels and picks.but high technology is making the archeologists work and time far more productive.
take,for example,the second 1981 flight of the space shuttle challenger.during that mission,a powerful,experimental radar was pointed at a lifeless stretch of desert in egypt called the selima sand sheet.to everyones surprise,the radar penetrated through the sand to the harder rock beneath.on the surface,there is a little indication that africas sahara desert was never anything but a desert.when the archeologists studied the radar images,they saw what seemed to be impossible: there was sand-buried landscape that was shaped by flowing water; traces of ancient riverbeds appeared to be over nine miles wide,far wider than most sections of the present-day nile river.today,the area is one of the hottest,driest desert in the world.
archeologists dug pits along the old river banks and found clues to the past: stream-rounded pebbles,stone-age axes,broken ostrich eggshells,and the shells of land snails.the archeologists were quite pleased with these findings.for years,theyd been finding stone axes scattered through the desert,and couldnt understand why.now we know that early humans were living on the banks of old rivers,and left their beautiful tools behind.some are so sharp that you could shave with them.
more recently,landsat 4,a special earth-mapping satellite,aided in the discovery of ancient mayan ruins in mexico.landsat can,with the help of false-color imagery,see through much of the area.armed with these maps,a five-person expedition took to the air in a helicopter.
by the end of the second day,the team found a stretch of walled fields that expedition members said look like old new england fences.they just go on,non-stop,for 40 miles.later in the week,an ancient village was pinpointed,as was the lost city of oxpemul,once found in the early 1930s but quickly reclaimed by the jungle.the findings made them able to map the extent of the mayan civilization in about five days.working on foot,it would have taken at least 100 years.
练习:
1.with the help of the space-shuttle-carrieD.radar, archeologists found
A.A.new stretch of the saharA.desert.
B.traces of ancient riverbeds under the saharA.desert.
C.some traditional archeological tools in the saharA.desert.
D.A.mountain beneath the saharA.desert.
2.which of the following is true of the sand-burieD.landscape?
A.it was an olD.avenue,
B.it was an undergrounD.river.
C.it was shapeD.by flowing water.
D.it was shapeD.by the olD.nile river.
3.the stream-roundeD.pebbles anD.stone-age axes which were founD.along the ancient river banks show that
A.an early human civilization once existeD.along the olD.riverbanks.
B.ancient people didnt know how to make weapons.
C.most species of animals in saharA.have disappeared.
D.early humans were gooD.at fighting with sharp weapons.
4.they in the seconD.line of the last paragraph refers to
A.olD.new englanD.fences.
B.the stretch of walleD.fields.
C.the expedition members.
D.ancient villages.
5.which of the following best summarizes the main information of the passage?
A.high-tech helps locate many fascinating archeological sites.
B.without high-tech, the archeologists work woulD.come to A.stop
C.high-tech is has taken the place of shovels anD.picks.
D.high-tech makes the archeologists work more fruitful.
【参考答案】1.B 2.C 3.A 4.B 5.D
求职需谨慎!10大迹象发现职业骗局
5个真相:解读新时代职业发展趋势
9个看似谎言的事实:你信吗?反正我信了
每天吃多少最健康?手长度来帮忙测一测!
低头党注意!常常玩手机的九大风险
世界网络哪家强?TOP20排行韩国第1香港第9
吃一口垃圾食品竟要运动这么久
华盛顿邮报力荐2017十佳读物 你看了吗
职场误区:营销人员嘴皮子溜就够了
纠结圣诞节送啥?科学家来支招 保证ta喜欢
卷福给圣诞老人手写了一封信:文采感人!
熊猫的世界原来不只是黑与白
路怒症成为交通事故的最大幕后黑手
全球气候抗暖表现大评比:丹麦第一中国47
这位圣诞老人出场时 万千少女都把持不住了
工作疲倦?是时候给自己来点挑战了
成功遭人嫉妒?这是最好的回答方式
老板再见!5种捷径外快赚够了就跑吧
美女们注意啦!记住这些,你的皮肤水嫩嫩!
美国枪击案:今年第355起
提前退休好不好
双11充气娃娃销量爆火 但存在安全隐患
告诉你的老板!10招提升员工幸福感
10部经久不衰的经典英国小说
妹子们找高的吧!夫妇身高差和幸福感成正比
你以为所有的蔬果都能减肥吗
扎克伯格给女儿的信双语全文
新手必看:化妆达人也会犯的15个错误!
当心!超高热量圣诞特饮里的甜蜜陷阱
2017经济学人年度好书:知识改变命运
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |