研究组专为参加2019年2月23日
Cereals and Legumes: A Partnership
Cereals are flowering grasses that sprout, flower, seed, and die in the space of a year, which is why gardeners refer to them as annuals. Grown for their seeds or kernels, cereals are excellent sources of energy: although they lack some amino acids, as well as calcium, vitamin A, and vitamin C, they provide starch and oil, and in some cases, considerable amounts of protein. Once ripe, the kernels are relatively easy to store, and they retain their nutrients for a long time. Even the stalks of cereals are useful as animal food, as bedding in stables and barns, and as a building material. A major drawback with cereals is that they depend on the soil for nitrogen. Without fertilization they eventually exhaust the fields they are growing in, but despite this, two cereals (wheat and barley) were the very first plants to be domesticated (grown for human use); and a third (rye) may have been cultivated, or even domesticated, at about the same time. Today, cereal crops including wheat, rice, maize, sorghum, millet, and oats provide most of the calories in the human diet.
Like cereals, legumes are annuals. ■ Some legumes are grown for animal fodder. Many other legumes, however, are cultivated for their seeds, which ripen in pods. The seeds are rich in B vitamins and iron, contain on average two times the protein but less starch than cereals, and can be eaten, sometimes pods and all, while they're still green. (Snow peas and green beans are familiar examples.) ■ Legumes are characterized by a long period of sequential ripening, during which a single plant may have ripe pods, green pods, and flowers, all at the same time, which means that a stand of legumes can be harvested again and again over several weeks. Like cereals, legumes can be dried and stored for later use (the pods open easily when dry), and again like cereals, legumes provide food for both people and animals. ■ However, legume plants add nitrogen to the soil, so when they are grown in the same fields as cereals, they can replace much of the nitrogen the cereals have depleted. ■
Growing cereals and legumes together is good for the fields, and eating them together is good for the farmers. In order to build and maintain body tissue, people need protein or more specifically, the amino acids in protein. Some amino acids are synthesized in the adult human body, but eight essential ones cannot be and have to come from food. Although all eight are present in animal protein, plant proteins are usually missing one or two. When cereals and legumes are eaten together, they provide all eight of the essential amino acids, a fact that the ancestors of early agriculturalists undoubtedly understood at least on a practical level and their descendants took advantage of that knowledge. In Asia, rice, wheat, and barley were grown along with soybeans; in India rice was paired with hyacinth bean, black gram, and green gram; in the African savanna, pear millet and sorghum were domesticated along with cow pea and Bambara groundnut; and in the New World, maize and Phaseolus beans in Central America and maize and groundnuts in South America were the bases for agriculture.
Cereals and legumes are technically dry fruits (they have a hard dry layer around their seeds). Early agriculturalists also experimented with growing succulent fruits like apples, olives, grapes, and melons, but most of these were brought into domestication much later than cereals and legumes, and in most
cultures they've always been supplementary foods rather than staples. Many of them are propagated vegetatively asexually by using a plant part such as a bulb or cutting rather than sexually through seeds, so they are more complicated to grow than cereals and legumes, and this may account for their typically late addition to agricultural assemblages. It should be noted, however, that recent research in Israel suggests that figs may have been domesticated at a site near Jericho in the Jordan Valley at about the same time as the first experiments with cereals and legumes, and some archaeologists believe that in New Guinea, tubers may have been domesticated long before other crops were imported.
1. According to paragraph 1, all of the following are advantages of cereals EXCEPT:
A. They provide large amounts of energy when consumed.
B. They store easily and retain nutrients for a long time.
C. They provide considerable amounts of calcium, vitamin A, and vitamin C.
D. They have multiple uses, including as bedding or building material.
2. According to paragraph 1, a major disadvantage of cereals is that they
A. cannot be used as animal food
B. must be planted in a different field every year
C. take a long time to ripen before they can be used or stored
D. use up all of the nitrogen in a field unless fertilizer is used
3. According to paragraph 2, one way in which legumes differ from cereals is that legumes
A. are a better source of starch
B. contain far more protein
C. take much longer to ripen
D. must be dried before being stored
4. According to paragraph 2, all of the following statements about legumes are true EXCEPT:
A. Legumes have pods that help seeds ripen quickly.
B. Legumes contain a lot of iron and B vitamins.
C. Legumes return nitrogen to the soil.
D. Legume plants can be harvested many times during a growing season.
5. The word “specifically” in the passage is closest in meaning to
A. precisely
B. importantly
C. frequently
D. likely
6. The word “undoubtedly” in the passage is closest in meaning to
A. possibly
B. typically
C. certainly
D. initially
7. Paragraph 3 supports which of the following ideas about amino acids
A. Amino acids are not produced by the human body and must be obtained from food.
B. Certain amino acids that people need for building and maintaining body tissue cannot be acquired from plant proteins.
C. When legumes or cereals are consumed alone, they do not provide all of the essential amino acids.
D. Legumes are missing many more of the eight essential amino acids than cereals are.
8. In paragraph 3, why does the author discuss crops grown in Asia, India, the African savanna, and the New World
A. To show how widely the understanding of the benefits of combining legumes and cereals was applied
B. To suggest that it was most effective for the same crops to be grown year after year in many parts of the world
C. To emphasize that proteins that come from plants were recognized as valuable in many parts of the world
D. To demonstrate that a wide variety of very different cereals and legumes could be grown together
9. The word “technically” in the passage is closest in meaning to
A. more complex than
B. generally understood to be
C. often confused with
D. scientifically classified as
10. The word “supplementary” in the passage is closest in meaning to
A. valued
B. rare
C. seasonal
D. extra
11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage. Incorrect choices change the meaning in important ways or leave out essential information.
A. Many of the cereals and legumes can be propagated asexually through offshoots, cuttings, tubers, bulbs and corns or sexually through seeds, which are less complicated to grow.
B. Fruits were typically domesticated later than cereals and legumes, possibly because they tend not to be propagated through seeds and are thus more complicated to grow.
C. Plants that are propagated sexually through seeds are generally much less complicated to grow than asexually propagated plants are.
D. In addition to being propagated asexually, rather than sexually through seeds, many fruits can be added and grown later in the season than cereals and legumes.
12. Paragraph 4 supports which of the following ideas about the figs that may have been domesticated in the Jordan Valley near Jericho
A. Their early domestication casts doubt on the idea that succulent fruits were grown much later than cereals and legumes.
B. They were a more important crop to inhabitants of the Jordan Valley than cereals and legumes were.
C. They are closely related to the plants domesticated in New Guinea before other crops were imported.
D. They are much easier to grow than any other succulent fruit.
13. Look at the four squares that indicate where the following sentence could be added to the passage.
Although they must be replanted each year, they can be grown for a variety of uses.
Where would the sentence best fit? Click on a square to add the sentence to the passage.
14. Drag your choices to the spaces where they belong. To review the passage, click on View Text. Answer Choices
A. Cereals, annual flowering grasses with usable stalks and nutritious seeds that dry and store well, were the first domesticated plants, but they must be grown with legumes to preserve soil nitrogen.
B. Legumes contain a large amount of protein and, when they are eaten with cereals, provide all the amino acids essential to humans.
C. Both the seeds and stalks of wheat and barley were eaten by early agriculturalists, who needed to take in enough nutrients and calories to work the fields.
D. Planting cereals and legumes together sped up their growing period, which meant that they could both be harvested many times over a period of several weeks to several months.
E. Cereals and legumes were typically domesticated well before succulent fruits, which are harder to cultivate, and became staples in early agricultural societies.
F. Because soil conditions in New Guinea and the Jordan Valley made it difficult to grow cereals such as wheat and barley, these regions began to cultivate figs and tubers instead.
参考答案
Q1C Q2D Q3B Q4A Q5A Q6C Q7BC Q8A Q9D Q10D
Q11B Q12A Q13A Q14 BCE
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