2020年8月26日托福阅读真题+题目+答案：Insect Senses

2020年8月26日托福阅读真题+题目+答案：Insect Senses

Insects have a variety of ways to sense the world. Although some insects are eyeless: most of them have a pair of compound eyes. If you examine a compound eye with a hand lens, you can see that it is an aggregate of many transparent hexagonal lenses. The light that passes through each lens stimulates a light-sensitive element beneath it. Thus, unlike the eye of a bird or a human, in which a single lens focuses the image onto the retina, the eye of an insect is, true to its name, a compound of many separate visual units, each a light-sensitive structure provided with its own lens. Compound eyes are less adept than our own eyes or birds’ eyes at resolving form and detail but they are far quicker to perceive movement. (Just think how difficult it is to snatch a fly with your hand.) The ability of compound eyes to resolve detail does, however, increase with the number of visual units that they contain. The wingless and largely inactive female of a firefly has only 600 visual units in her compound eyes, but the winged male, which must find the female by visual means，has 5,000 in his eyes. Dragonflies, which require great visual acuity because they catch their often tiny insect prey while flying, may have a total of 56,000.

Insects, like birds and humans, see colors—not surprising since so many of them are attracted to flowers with bright colors, especially yellow and blue. Although butterflies, like hummingbirds, are attracted to red flowers, most other insects do not see as far into the red range as do we and most birds, but unlike us and like some birds, they see into the near ultraviolet range. Not surprisingly, some flowers have markings that are visible only in the ultraviolet range and that often act as “nectar guides” indicating where the nectar is.

。。。。。余下托福阅读真题省略！

1.The word “aggregate” in the passage is closest in meaning to

A collection 

B part 

C growth 

D instrument

2.According to paragraph 1, compound eyes are particularly good for

A perceiving slight changes in light 

B resolving form and detail 

C providing a broad field of vision 

D detecting motion

3.Which of the following can be inferred from paragraph 1 about female fireflies?

A They have sharper vision than dragonflies.

B They can see more details than male fireflies can.

C They do not need to see as well as male fireflies in order to find food or mates.

D They are more active at an earlier stage of life than as adults.

。。。。。余下托福阅读题目省略！

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