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 from 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.

　　Before the waves reach South America, the second piece of the comet lands in Argentina.

　　Earthquakes and volcanoes are 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, and temperature around the world falls 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 remain alive.

　　Could it really happen? In fact, it has already happened more than once in the history of the Earth. The

　　dinosaurs (恐龙) 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?

　　请根据以上文章，完成下列表格：

　　Reasons 　　Results 　　One piece hits the South Atlantic at 200 times 71 72 the speed of sound.

　　 　　The sea boils and a huge hole is made in the seabed. A tsunami(海啸) hits southern Africa, 73 cities on the African coast, and 74 millions of people. 　　A 75 76 happens when the four-kilometer-wide piece of comet enters the Earth's 77 . 　　The sun is hidden by clouds of dust and the temperature falls to almost zero, 78 crops. Wars break out for food and only 10 million people remain. The human beings are 79 the danger of 80 out.