| Certainly no creature in the sea is stranger than the common sea cucumber (海参). All living creatures, especially human beings, have their features, but everything about the little sea cucumber seems unusual. What else can be said about an unusual animal that eats mud, feeds almost continuously day andnight but can live without eating for long periods, and can be poisonous but is considered eatable? For some fifty million years in spite of all its strange features, the sea cucumber has lived on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow Water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to suck up mud or sand and digest whatever nutrients are present. Sea cucumbers come in a variety of colors, black to reddish-brown to sand-color and nearly white. One form even has vivid purple feelers. Usually the creature are cucumber-shaped — where their name comes from - and because they live in rocks, this shape, combined with flexibility, enables them to press into crevices (缝隙) where they are safe from animal eater and ocean currents. Although they have greedy desire for food, eating day and night, sea cucumbers have the ability to become still and live at a low metabolic (新陈代谢) rate — feeding s little or not at all for long periods, so that the living things in the ocean that provide their food have chance to increase by a large amount. If it were not for this natural ability, they would swallow all the food available in a short time and would probably starve themselves out of existence. But the most impressive thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs. When attacked, it forces all its organs in its body out into water. It also removes attached structures such as feelers. The sea cucumber will get rid of its organs and grow itself again if it is attacked or even touched; it will do the same if the surrounding water temperature is too high or if the water becomes too polluted. |
| 1. According to the passage, why is the shape of sea cucumbers important? |
| A. It makes them attractive to fish. B. It helps them to digest their food. C. it helps them to protect themselves from danger. D. it makes it easier for them to move through the mud. |
| 2. The fourth paragraph of the passage mainly discusses ______. |
| A. the reproduction of sea cucumbers B. the food sources of sea cucumbers C. the eating habits of sea cucumbers D. the danger to sea cucumbers' existence |
| 3. What can he inferred about the defense system of the sea cucumber? |
| A. They are similar to those of most sea creatures, B. They are very sensitive to the surroundings. C. They require group cooperation. D. They are almost useless. |
| 4. What would be the best tithe for the text? |
| A. The Variety of Sea Cucumbers B. The Sources of Sea Cucumbers C. The Similarity of Sea D. The Strange Creature — Sea Cucumbers |