Haveyouwonderedwhyyouhavetwoeyesandwhytheyaresetcloseto...

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Have you wondered why you have two eyes and why they are set close together on the front of your face？The reasons are simple and important.

Your eyes are like two small cameras. A camera catches an image(影像) of an object and records it on film. Similarly, when you look at something, each eye takes in what it sees and sends this image to the back of the eyeball. Because your eyes are set close together, they see the world from about the same height but from a little different angles(角度). While your right eye sees an object a little to the right, your left eye sees the same object a bit to the left. Working as a team, the eyes send the images to your brain, then your brain put them together and you see a single image in the center.

Seeing in stereo means seeing with two eyes working tighter, which is called stereoscopic sight. This allows you to see the world in 3-D. Seeing depth(深度) helps you to judge how far it is between you and the objects you see, and then adjust(调整) to the changing angle so that you can see something clearly when you move closer or farther away. If images are coming from only one eye, however, height and width(宽度)—can be perceiced. So if you see with one eye, you will get a 2—D image, as in a photograph.

Now consider why your two eyes are on the front of your face. Think of other animals just like you. They are all hunting(猎杀) animals, like lions and tigers. This provides a field of sight about 180 degree wide, which is called binocular sight. On the other hand, animals that are hunted have eyes on the sides of the head, which provides nearly 360—degree field of sight. However, they don’t have stereoscopic sight. It is difficult for them to judge how far a danger is.

With both stereoscopic and binocular sight, humans and hunting animals share the ability to see from side to side and to judge how far it is from other objects. If you think it would be great to have another kind of sight, perhaps with hundreds of tiny eyes like many insects(昆虫) do, think again! Each tiny insect eye sees only a tiny part. Besides, what if you needed glasses? Be glad for the eyesight that you have.

1. In Paragraph 2, the writer wants to .

A. tell us how our two eyes works B. show the importance of eyes

C. compare our eyes with cameras D. suggest using two eyes properply

2. The underlined word “perceiced”in Paragraph 3 means .

A. set B. taken C. seen D. made

3. In the last paragraph, the writer thinks that “seeing in stereo” .

A. is similar to the way a camera works B. is an ability humans are lucky to have

C. would be better for a wilder field of sight D. helps people to have better sight than animals

4. What is probably the best title for this passage?

A. Seeing in stereo B. Protecting your eyes C. Treasuring your eyes D. Seeing with eyes

【回答】

1. 主旨题。由第一段第一句“Your eyes are like two small cameras.”可知作者以照相机对比我们双眼的运作机制，故选A。