解放军文职招聘考试光的种类及其特征

 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.

1. 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

2. The underlined word “luminous” means_______.

A. visible B. all colors C. giving off light D. sunlight

3. ________ have light of their own.

A. The sun and the moon B. The stars and the earth

C. The sun and the stars D. The moon and the earth

4. Which of the following is true?

A. All the things you can see give off light.

B. Light from the book is much shorter than that from the moon.

C. The moment you open your eyes the light from the book travels to your eyes.

D. Light travels so fast that there is no time for you to read.

(1—4 BCCC)

【答案与解析】本文介绍了光的种类及其特征。

1. B。细节题。根据文章第文章第 2 段第 1 句 …it sends to your eyes some of the light which falls on it可推知此题答案为 B。

2. C。词义猜测题。根据文章第 2 段第 2 句 Some of the things you see give off light of their own 和第 4 句 Such things are luminous 可推知此题答案为 C。

3. C。推断题。根据文章第 1 段第 3 句 The sun, the stars, a lighted lamp are examples that can be seen by their own light可推知此题答案为 C。

4. C。推断题。根据文章最后一段第 1 句 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 可推知此题答案为 C。