Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals.
Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year. The seas plankton generates more than twice as much.
Despite its enormous food potential, little effort was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the seas resources loom even more important as a means of feeding an expanding world population.
No one yet has seriously suggested that planktonburgers may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists.
One type of plankton that seems to have great harvest possibilities is a tiny shrimplike creature called krill. Growing to two or three inches long, krill provide the major food for the giant blue whale, the largest animal ever to inhabit the Earth. Realizing that this whale may grow 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily.
Krill swim about just below the surface in huge schools sometimes miles wide, mainly in the cold Antarctic. Because of their pink color, they often appear as a solid reddish mass when viewed from a ship or from the air. Krill are very high in food value. A pound of these crustaceans contains about 460 caloriesabout the same as shrimp or lobster, to which they are related.
If the krill can feed such huge creatures as whales, many scientists reason, they must certainly be contenders as new food source for humans.
1.Which of the following best portrays the organization of the passage?
A.The author presents the advantages and disadvantages of plankton as a food source.
B.The author quotes public opinion to support the argument for farming plankton.
C.The author classifies the different food sources according to amount of carbohydrate.
D.The author makes a general statement about plankton as a food source and then moves to a specific example.
2.According to the passage, why is plankton regarded to be more valuable than land grasses?
A.It is easier to cultivate.
B.It produces more carbohydrates.
C.It does not require soil.
D.It is more palatable.
3.Why does the author mention planktonburgers?
A.To describe the appearance of one type of plankton.
B.To illustrate how much plankton a whale consumes.
C.To suggest plankton as a possible food sources.
D.To compare the food values of beef and plankton.
4.What is mentioned as one conspicuous feature of krill?
A.They are the smallest marine animals.
B.They are pink in color.
C.They are similar in size to lobsters.
D.They have grass like bodies.
5.The author mentions all of the following as reasons why plankton could be considered a human food source except that it is ___.
A.high in food value.
B.in abundant supply in the oceans.
C.an appropriate food for other animals.
D.free of chemicals and pollutants.
第37篇答案:DBCBD
[动词的时态]过去进行时
[动词的语态]need/want/require/worth
[动词的时态]比较since和for
[动词的时态]用现在进行时表示将来
[独立主格]独立主格
[动词的时态]现在进行时代替将来时
[动词的时态]一般现在时代替现在完成时
[动词的语态]短语动词的被动语态
[动词的时态]延续动词与瞬间动词
[动词的时态]一般现在时代替一般过去时
[倒装]as, though 引导的倒装句
[动词的时态] used to / be used to
[独立主格]with的复合结构作独立主格
[动词的时态]一般过去时的用法
[动词的时态]不用进行时的动词
[动词的时态]时态与时间状语
[动词的语态]主动形式表示被动意义
[主谓一致]主谓一致中的靠近原则
[动词的语态]不用被动语态的情况
[虚拟语气]真实条件句
[分词]分词作表语
[动词的时态]一般现在时的用法
[动词的时态]be to和be going to
[句子的种类]句子的种类
[分词]连词+分词(短语)
[动词的时态]since的四种用法
[动词的语态]let 的用法
[动词的时态]用一般过去时代替过去完成时
[分词]分词的时态
[句子的种类]祈使句结构
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |