The year is 2094. It has been announced that a comet （彗星）is heading towards the earth. Mos

The year is 2094. It has been announced that a comet （彗星）is heading towards the earth. Most of it will miss our planet, but two pieces will probably hit the southern half of the earth.
On 17 July, a piece of 4 kilometers wide comet enters the Earth’s atmosphere with a massive explosion（爆炸）. About half of the piece is destroyed, but the remaining part hits the South Atlantic at 200 times the speed of sound. The sea boils and a huge hole is made in the seabed. Huge waves are created and spread outwards form the hole. The wall of water, a kilometer high, rushes towards southern Africa at 800 kilometers an hour. Cities on the African coast are totally destroyed and millions of people are drowned（淹死）.
Before the waves reach South America, the second piece of the comet lands in Argentina. Earthquakes and volcanoes ash set off in the Andes Mountains. The shock waves move north into California and all around the Pacific Ocean. The cities of Los Angeles, San Francisco and Tokyo are completely destroyed by earthquakes. Millions of people in the southern half of the earth are already dead, but the north won’t escape for long. Because of the explosions, the sun is hidden by clouds of dust, temperatures around the world fall to almost zero. Crops are ruined. The sun won’t be seen again for many years. Wars break out as countries fight for food. A year later, no more than 10 million people remain alive.
Could it really happen? In fact, it has already happened more than once in the history of the earth. The dinosaurs were on the Earth for over 160 million years. Then 65 million years ago they suddenly disappeared. Many scientists believe that the Earth was hit by a piece of object in space. The dinosaurs couldn’t live through the cold climate that followed and they died out. Will we meet the same end?
【小题1】What is mainly described in the passage?A．A historic discovery.B．An event in imagination.C．A research on space.D．A scientific adventure.【小题2】When the first piece hits the South Atlantic, it causes .A．an earthquakeB．hungerC．an Earth explosionD．huge waves【小题3】Why can’t the northern half of the earth escape for long?A．Because the land is covered with water.B．Because the light and heat form the sun cannot reach the earth.C．Because people there cannot live at the temperature of zero.D．Because wars break out among countries.【小题4】By giving the example of dinosaurs, the author tries to prove .A．animals could not live in the cold climateB．what happened 65 million years ago was an invented storyC．the human beings will die out in 2094D．the Earth could be hit by other objects in spaceB

(答案→)B 解析：作者讲述了 2094 年彗星碎片撞击地球后可能产生的灾难，其目的是警告人们在地球的未来可能会发生灾难。【小题1】主旨题：文章描述了人类在2094年可能会遭遇的灾难。这些事情只是一种想象而已。选B。【小题2】细节题：根据文章第二段Huge waves are created and spread outwards form the hole.可知，应该选D。【小题3】细节题：文章第三段中提到，南半球的数以万计的人已经死了，而北半球也逃脱不了 这种厄运。因为太阳多年照不到地球，地球上的温度几乎降到了零度。植物遭到了破坏，食物缺乏，导致战争。所以，一切的根源在于B选项。选B。【小题4】推理题：答案在文章最后一段，作者举恐龙这一例子是为了说明地球很有可能再次遭 遇袭击。选D。

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