网址:http://m.1010jiajiao.com/timu_id_825100[举报]
She doesn’t like the book you are interested .
A. which, in B. which, X C. who, in D. that, X
查看习题详情和答案>>
You can not see any object unless light from that object gets into your eyes. Some of the things you see give off light of their own. The sun, the stars, a lighted lamp are examples that can be seen by their own light. Such things are luminous. Most of the things you see are not giving off light of their own. They are simply reflecting light that falls on them from the sun or some other luminous bodies. The moon, for example, does not give off any light of its own. It is non-luminous. You see it because sunlight falls on it and some of it reflects in our direction. So moon light is only second hand sunlight.
When you look at a book, it sends to your eyes some of the light which falls on it, and you see the book. If light could be kept out from where you are so that there would be no light for the book to reflect, then you could not see the book even with your eyes wide open.
Light travels so fast that the time in which it travels from the book you are reading to your eyes is so short as if there were no time at all. Light reaches us from the moon, which is about 380 000 kilometers away, in only a little more than a second.
51. You can see the book because_______.
A. your eyes are close to it B. it reflects some of the sunlight
C. it has light of its own D. your eyesight can get to it
52. The underlined word “luminous” means_______.
A. visible B. all colors C. giving off light D. sunlight
53. Light traces about _________ kilometers per second.
A. 380 000 B. 300 000 C. 400 000 D. 190 000
54. Which of the following is true?
A. The moment you open your eyes the light from the book travels to your eyes.
B. Light from the book is much shorter than that from the moon.
C. All the things you can see give off light.
D. Light travels so fast that there is no time for you to read.
55. What is the main idea of the passage?
A. You can see and read a book because you open your eyes.
B. Some objects are luminous, some not.
C. You can see things because of light.
D. Light travels very fast so you cannot notice it.
查看习题详情和答案>>