题目内容：

    Everybody knows that Earth spins from west to east. That is to say, it appears to be spinning counterclockwise(逆时针)when viewed from above the North Pole.

But what if Earth started spinning the other way?

Scientists from Germany have made a computer simulation(模拟)in which Earth spins in the opposite direction-clockwise when viewed from above the North Pole. This showed them some interesting things about the weather and topography(地形地貌)on Earth, live Science reported.

As Earth spins in a counterclockwise direction, it shapes ocean currents(洋流).The direction of the spin, together with wind, produces different weather around the globe(全球).

But a backwards spin changes the ocean currents and winds. Therefore, the climate(气候)is different. Western areas of continents(大陆)on Earth cool down as the eastern parts warm up.  Winters become even colder in northwestern Europe, while eastern Russia becomes warmer than before. Rain no longer falls on the planet's wettest places.

Another result of a backward spin is that Earth becomes greener. Scientists found that global desert(沙漠)areas reduce from 42 million square kilometers to 3l. million square kilometers. This may have something to do with the changing climate.

Therefore, you can see rich green landscapes from Central Africa to the Middle East, which are mostly covered by deserts now. More surprisingly, the Sahara Desert becomes an oasis(绿洲).

_______ . They just appear in some places that they never appeared in before. Deserts would cover North America, where countries like the United States and Canada lie. Sand dunes(沙丘)would replace the Amazon rainforest in South America.

A backward spin would keep the major characteristics of Earth's topography, such as the size, shapes and positions of continents and oceans. But it would also change the interactions between circulating(环流)air, ocean and topography, lead scientist Florian Ziemen told Live Science.

1.Why would the climate be different if Earth spins backwards?

A.Because there won't be any more large oceans.

B.Because the ocean currents and winds will be changed.

C.Because it will change the amount of sunlight that Earth can receive.

D.Because Earth will become greener without deserts.

2.What will a backwards spin bring to the Earth?

A.Winters will become colder. B.No rain will fall in summer.

C.Eastern Russia will become warmer. D.The Sahara Desert will become smaller.

3.The story tells us that ________ .

A.Earth used to spin in the opposite direction

B.a backwards spin would cause interesting changes on Earth

C.global desert areas have become smaller

D.a backwards spin would change Earth's topography completely

4.Which of the following sentences can be put at the beginning of the eighth paragraph?

A.Sadly, deserts would cover North America. B.Luckily, deserts would disappear(消失).

C.Anyway, deserts would replace the Amazon rainforest. D.However, deserts don't disappear.