英语六级阅读例句练习附详解：视力研究

　　蜜蜂的眼睛是复眼，用于导航。它的眼睛有15000个面，把它看到的物体分割为马赛克式的小点。[4]有了这种视觉特点，蜜蜂看到的太阳只是一个小点，一个不变的参照点。所以，它的眼睛是一个极好的导航仪器，能不断地量度飞行的线路与太阳的角度。蜜蜂的眼睛还能测量飞行的速度。如果这样还不能让我们人类20/20的完美视力显得微不足道的话，蜜蜂还能看到紫外线，这是我们人类无法看到的。因此，当我们与别的特种相比时,人类认为“完美的视力”实际上很有局限性的。然而，对于人类的眼睛还是有很多可以称赞的：在所有哺乳动物当中，只有人类和某些灵长类动物能享受分辨颜色的喜悦。

　　1. The Snellen eye chart measures one'seyesight by__________________.

　　A) the number of lines he reads

　　B) the distance he stands away from the chart

　　C) the speed at which he recognizes the letters

　　D) several integrative factors

　　2. How is hawk's eyesight better than ours?

　　A) It can identify small items more quickly than we do.

　　B) It can see ai a longer distance than we do.

　　C) It has more cones in che retina than we do.

　　D) It has bigger eyes than we do.

　　3. Monocular vision enables the kingfisher to__________________.

　　A) avoid farsightedness

　　B) be able to see underwater

　　C) move one eye at a time

　　D) focus its eyes on the prey

　　4. A bee finds its direction by_______________________.

　　A) dividing what it sees into thousands of dots

　　B) constantly gauging its flying speed

　　C) using the sun as a constant point of reference

　　D) measuring the angle of the sun

　　5. What is the main idea of the passage'?

　　A) The differences between human eyes and other species' eyes.

　　B) The advantages of other species' eyes in comparison with human eyes.

　　C) The factors that make other species' eyes better than human eyes.

　　D) The standard that determines me "perfect vision” of human eyes.