Insects´ lives are very short and they have many enemies, but they must survive long enough to breed and perpetuate their kind. The less insect like they look, the better their chance of survival. To look “inedible” by resembling or imitating plants, is a deception widely practiced by insects. Mammals rarely use this type of camouflage, but many fishes and invertebrates do.

The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called “measuring worm” of “inchworm”. It walks by arching its body, then stretching out and grasping the branch with its front feet, then looping its body again to bring the hind feet forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed.

Walkingsticks, or stick insects, do not have to assume a rigid, twiglike pose to find protection, they look like inedible twigs in any position. There are many kinds of walkingsticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live.

Leaves also seem to be a favorite object for insects to imitate. Many butter flies can suddenly disappear from view by folding their wings and sitting quietly among the foliage that they resemble.

1. What is the main subject of the passage?

A. Catepillars that live in trees

B. The feeding habits of insects

C. How some insects camouflage themselves

D. Insects that are threatened with extinction

2. In lines 1, the word “enemies” refers to.

A. other creatures competing for space

B. extreme weather conditions

C. creatures that eat insects

D. inedible insects

3. According to the passage, how does the stick caterpillar make itself look like a twig?

A. By holding its body stiff and motionless

B. By looping itself around a stick

C. By changing the color of its skin

D. By laying its body flat against a branch

4. Which of the following is true of stick insects?

A. They resemble their surroundings all the time.

B. They make themselves look like other insects.

C. They are camouflaged only when walking.

D. They change color to make themselves invisible.

5. Which of the following are not mentioned in the passage as objects that are imitated as a means of protection?

A. Thorns B. Flowers C. Leaves D. Sticks

6.In which paragraph does the author describe the way in which stick caterpillars move?

A. Paragraph one B. Paragraph two

C. Paragraph three D. Paragraph four

查看解析

查看解析

选择答案：正确错误查看解析

选择答案：正确错误查看解析

查看解析