2021年7月31日雅思考试机经回忆完整版(3)

2021年7月31日雅思考试机经回忆完整版(3) 关于这个问题下面小编就来为各个考生解答下。

2021年7月31日雅思考试机经回忆完整版(3) 

2021.07.31

READING

Passage 1

Topic

Food security Food future

A crisis is looming: To feed our growing population, we' II need to double food production.

Yet crop yields aren ’t increasing fast enough, and climate change and new diseases threaten the limited varleties we’ve come to depend on for food. Luckily we still have the

seeds and breeds to ensure our future food supply- but we must take steps to save them.

Six miles outside the town of Decorah, lowa, an 890-acre stretch of rlling fields and woods called Heritage Farm is letting its crops go to seed. It seems counterintuitive, but

then everything about this farm stands in stark contrast to the surrounding acres of neatly rowed corn and soybean fields that typify modern agriculture. Heitage Farm is devoted to

collecting rather than growing seeds. It is home to the Seed Savers Exchange, one of the largest non-govemment-owned seed banks in the United States.

In 1975 Diane Ott Whealy was bequeathed the seedlings of two heirloom plant varieties that her great grandfather had brought to America from Bavaria in 1870: Grandpa Ott' s moming glory and his German Pink tomato. Wanting to preserve such unique varieties, Dlane and her husband, Kent, decided to establish a place where people could store and trade the seeds of their own past. The exchange now has more than 13,000 members and keeps in its walk-in coolers, freezers, and root cellars the seeds of many thousands of heirloom varieties. The farm grows a glorious profusion of select vegetables, herbs, and flowers around an old red bar that is covered in Grandpa Ott' s stunningly deep purple moming glory blossoms.

“Each year our members list their seeds in this," Diane Ott Whealy says, handing over a copy of the Seed Savers Exchange 2010 Yearbook(Q6)。 It is as thick as a big-city elephone directory, with page after page of exotic beans, garlic, potatoes, peppers,apples, pears, and plums- each with its own name, personal history, and distinct essence.

There’s an apple known as Beautiful Arcade, a“ yellow fruit splashed with red" ; one named Prairie Spy, described as“ precocious”; another dubbed Sops of Wine that dates back to the Middle Ages. There' s an Estonian Yellow Cherry tomato obtained from“ an elderly Russian lady”in allin, a bean found by archaeologists searching for pygmy elephant fossils in New Mexico, a Persian Star garic from“ a bazaar in Samarkand."

Heirloom vegetables have become fashionable in the United States and Europe over the past decade, prized by a food movement that emphasizes eating locally and preserving the flavor and uniqueness of heirloom varieties. Found mostly in farmers markets and boutique groceries, heirloom varieties have been squeezed out of supermarkets in favor of modem single-variety fruits and vegetables bred to ship well and have a uniform appearance, not to enhance flavor. But the movement to preserve heirloom varieties goes way, beyond America’s renewed romance with tasty, locally grown food and countless vareties of tomatoes. It' s also a campaign to protect the world' s future food supply.

Most of us in the well-fed world give ltte thought to where our food comes from or how it's grown. We steer our shopping carts down supermarket aisles without realizing that the apparent bounty is a shiny stage set held up by increasingly shaky scaffolding. We' ve been hearing for some time about the loss of flora and fauna in our rainforests. Very ltle.

by contrast, is being said or done about the parallel erosion in the genetic diversity of the foods we eat.

Food varietles extinction is happening all over the world- and it' s happening fast. In the United States an estimated 90 percent of our histoic fruit and vegetable varieties have vanished. Of the 7 ,000 apple varieties that were grown in the 1800s, fewer than a hundred remain. In the Philippines thousands of varieties of rice once thrived; now only up to a hundred are grown there. In China 90 percent of the wheat varieties cultivated just a century ago have disappeared. Experts estimate that we have lost more than half of the world’s food varieties over the past century. As for the 8,000 known livestock breeds, 1,600 are endangered or already extinct.

Why is this a problem? Because if disease or future climate change decimates one of the handful of plants and animals, we’ve come to depend on to feed our growing planet, we might desperately need one of those varieties we’ve let go extinct. The precipitous loss of the world’s wheat diversity is a particular cause for concern. One of wheat' s oldest adversaries, Puccinia graminis, a fungus known as stem rust, is spreading across the globe. The pestilence’s curent incaration is a virulent and fast-mutating strain dubbed Ug99 because it was frt ientified in Uganda in 1999. It then spread to Kenya, Ethiopia,Sudan, and Yemen. By 2007 it had jumped the Persian Gulf into lran. Scientists predict that Ug99 will soon make its way into the breadbaskets of India and Pakistan, then ifiltrate Russia, China, and- with a mere hitch of a spore on an airplane passenger’s shoe- our hemisphere as well.

Roughly 90 percent of the world’s wheat is defenseless against Ug99. Were the fungus to come to the US. an estimated one bllion dollars’worth of wheat would be at risk.

Scientists project that in Asia and Arica alone the portion of wheat in imminent danger would leave one blion people without their primary food source. A significant famine crisis

is inevitable, according to Rick Ward of the Durable Rust Resistance in Wheat project at Comell University.

The world' s population is expected to reach seven bllion people this year. By 2045 it could grow to nine bllion. Some experts say we" II need to double our food production to keep up

with demand as emerging economies consume more meat and dairy. Given the added challenges posed by climate change and constantly mutating diseases like Ug99, it is becoming ever more urgent to find ways to increase food yield without exacerbating the genetic anemia coursing through indutialized agriculture ' s ostensible abundance. The world has become increasingly dependent upon technology-driven, nesse-its-al solutions to its problems. Yet the best hope for securing food' s future may depend on our ability to preserve the locally cultivated foods of the past.

1-7为判断题

1. Heritage Farm is dfferent from other farms in the area. True

2. Most similar farms are larger than the SSE. False

3. Diane Ott Whealy's grandfather told her knowledge aboul heirloom plant varieties. Not Given

4. Diane and her husband selected what to plant. True

5. Seeds fom SSE are kept ouldoor. False

6. Seed Savers Exchange Yearbook is in the alphabet order. Not Given

7. Seed Savers Exchange Yearbook contains how the seeds are preserved. False

8-13题为填空题

8. Supermarkets hope the products they sold all have a standard appearance.

9. Although people may know that many plants are disappearing from rainforests, they may not realize that their food variety is also being damaged.

10. In the United States less than 100 varieties of apples have survived, and all other varieties have disappeared.

11. Researchers estimate that 50 percent of food types no longer exist.

12. According to Rick Ward if the current trend of food diversity loss continues, another famine may break out in the future.

13. As the world population continues to grow, we'll need to rais our food production two times .

Passage 2

Topic

The Internal Clock

内容方面

科学家研究生物钟的规律做了- .系列研究。在植物、尼虫身上做实验。文章讲述了研究的一-些发展，期间有人对先前研究提出质疑。有人提出生物各自的生物钟周期有些些许不同。有人提出并不是人体内有一" 个生物钟，而是每一个细胞中 都有相关基因控制生理节奏。最后提出未解决的问题:不同生物之间的生物钟是如何同步的，以及生物钟与太阳周期运动的关系。

14-18为匹配题

14.support from earlier research on insects F

15. criticism of the way the data was analysed D

16.reference to a test on plant A

17. statement that creatures have slight dffterent clocks E

18. reference of a theory that tries to explain the phenomenon c

19-22为填空题

SCN can perccive 19 daylight connected to the eye. Some years later, research involved 20 fruit flies show that they have 21 genes in their cells. Research reveals a 22 circadian cycle.

23-26为多选题

23 24 Which two problems are mentioned linked to intemal clock?

C failure of workers on night-shift

D increase in traffic casualties in special time of a day

25- 26 Which two problems remain to be solved

C why internal clocks in an organism synchronize with one another

D how the internal clock relates to the Sun's rhythm

由于篇幅的问题，以上只是一部分，更多内容请继续关注我们中国教育在线外语频道。