問題詳情

B.Everyone’s eyelids close and open rapidly, or blink, for any number of reasons. One reason is that the eyes are protectingthemselves from something that is irritating them. Another reason is that they are protecting themselves from a bright light. Athird reason is that they are trying to keep themselves free from dirt and dust.Every time you blink your eyes, you are actually crying, or producing tears. These tears keep your eyes wet. So that when anirritating substance, such as a bit of dirt, gets into your eye, your eyelids close and the tears try to wash away the dirt. A personblinks his or her eyes about 25 times per minute.Every person has a blind spot. A blind spot is the point where you may be facing a small object and not be able to see it. Thereason everyone has a blind spot is that there is one point on the retina where the optic nerve leaves your eye. No pictures orimages are received because the point is not sensitive to light.Try this experiment to find out where your blind spot is. Mark each side of this page with a visible dot. Hold this page about12 inches in front of you.Close your left eye and leave your right eye open. Look only at the dot on the left. Now move the page slowly toward yourface, and then move it slowly away from your face. As you move it away, at a certain point the dot at the right side disappearstotally. It is at that point that the dot falls exactly on your blind spot.Just as you are either right-handed or left-handed, so are you either right-eyed or left-eyed. That means one of your eyes isstronger, or more dominant, than the other. Here’s another experiment you can do to find out which is your dominant eye. Hold apencil vertically at arm’s length in front of you and at eye level. With both your eyes open, line up the pencil with a shelf, picture,clock or something else on the wall. First close one eye, then the other. Did the pencil stay in the same place with one eye open?Did it seem to move to the side of the other eye? Whichever eye was open when the pencil lined up with your object on the wallis your stronger, or dominant, eye.
36. According to the article, why do you blink your eyes?
(A) to protect them from dirt and dust
(B) to protect them from a bright light
(C) to protect them from irritating substances
(D) all of the above

參考答案

答案：D
難度：簡單0.833333
統計：A(1),B(0),C(0),D(5),E(0)

內容推薦

內容推薦