浙江省杭州市塘栖中学高中英语必修三：Unit4Readingquiz每课一练.doc

I. Fill in the blanks. Finally about 2.6 million years ago some small ______ animals, now with hands and feet, appeared and _______ all over the earth. _____ they have, ____________, become the most important animals on the planet. But they are not ____________ the earth very well. They are putting too much _____________ into the ____________, which ________ heat _____ escaping from the earth into space. ________________, many scientists believe the earth may become too hot to live on. So _______ life will continue on the earth for millions of years to come will __________ whether this problem can be solved. II. Task-based reading. Why do stars twinkle? Watching stars on a moonless night can be an interesting experience. Millions of stars twinkle as if they were playing hide-and-seek with one’s eyes. Why do stars twinkle? (1)______ And the light from the stars travels a very long distance to reach us. Actually very little of the light finally manages to reach us. Besides, it passes through the earth’s atmosphere before reaching us. As the light enters the atmosphere, something like dust interferes (干扰) its path. So, sometimes it is visible, and sometimes it is not. This effect is called twinkling.[来源:Z#xx#k.Com] (2)______ Well, that’s because they are not stars at all. They are planets. Planets do not twinkle because unlike stars, they do not have their own light. They are like the moon. They reflect light from the sun. (3)______ A star is born when lots of different gases, mainly hydrogen (氢) get together. The gas particles (微粒) attract each other and slowly get compressed to form a huge mass of gases. And, as this mass grows, the temperature inside grows too, until such time when it bursts like a bomb. This explosion (爆炸) creates a gas called helium (氦). The helium becomes its fuel and it continues burning. Thus a star is born. [来源:金太阳新课标资源网] No wonder the heavier stars burn more furiously. They have bigger explosions, where more helium is re