每日一练：职称英语考试综合类每日一练(2019/11/5)
【单选题】
Food Fright
Experiments under way in several labs aim tocreate beneficial types of genetically modified (GM) foods, including starchierpotatoes and caffeine-free coffee beans. Genetic engineers are even trying totransfer genes from a cold-winter fish to make a frost-resistant tomato.
A low-sugar GM strawberry now in the works mightone day allow people with health problems such as diabetes to enjoy the littledelicious red fruits again. GM beans and grains supercharged with protein mighthelp people at risk of developing kwashiorkor. Kwashiorkor, a disease caused bysevere lack of protein, is common in parts of the world where there are severefood shortages.
Commenting on GM foods, Jonathon Jones, aBritish researcher, said: "The future benefits will be enormous, and thebest is yet to come".
To some people, GM foods are no different fromunmodified foods. "A tomato is a tomato," said Brian Sansoni, anAmerican food manufacturer.
Critics of GM foods challenge Sansoni'sopinion. They worry about the harm that GM crops might do to people, otheranimals, and plants.
In a recent lab study conducted at CornellUniversity, scientists tested pollen made by Bt corn, which makes up one-fourthof the U.S. corn crop. The scientist sprinkled the pollen onto milkweed, aplant that makes a milky juice and is the only known food source of the monarchbutterfly caterpillar. Within four days of munching on the milkweed leaves,almost half of a test group of caterpillars had died. "Monarchs areconsidered to be a flagship species for conservation." said Cornellresearcher Linda Raynor. "This is a warning bell."
Some insects that are not killed by GM foodsmight find themselves made stronger. How so? The insecticides used to protectmost of today's crops are sprayed on the crops when needed and decay quickly inthe environment. But GM plants produce a continuous level of insecticide.Insect species feeding on those crops may develop resistance to the plants andcould do so in a hurry, say the critics. Insects may also develop a resistanceto the insecticide Bt.
At the forum on GM food held last year inCanada. GM crops that have been made resistant to the herbicide mightcrossbreed with wild plants, creating "superweeds" that could takeover whole fields.
So where do you stand? Should GM food be bannedin the United States, as they are in parts of Europe? Or do their benefitsoutweigh any of the risks they might carry?
1. Paragraphs 1,2&3 tries to give the ideathat
A) GM foods may bring about great benefits tohumans.
B) We cannot recognize the benefits of GM foodstoo early.
C) GM foods may have both benefits and harm.
D) GM foods are particularly good to thekwashiorkor patients.
2. Why is the case of the pollen-sprayedmilkweed citied in Paragraph 6?
A) It is cited to show GM foods can killinsects effectively.
B) It is cited to show GM foods contain moreprotein.
C) It is cited to show GM foods also have adark side.
D) It is cited to show GM foods may harm crops.
3. What happens to those insects when notkilled by the spray of insecticide?
A) They may lose their ability to produceoffspring.
B) They may have a higher ability to adapt tothe environment.
C) They move to other fields free frominsecticide.
D) They never eat again those plants containinginsecticide.
4. Which of the following statements concerningbanning GM foods is true according to the passage?
A) Underdeveloped countries have banned GMfoods.
B) Both Europe and the U.S. have banned GMfoods.
C) Most European countries have not banned GMfoods.
D) The United States has not banned GM foods.
5. What is the writer's attitude to GM foods?
A) We cannot tell from the passage.
B) He thinks their benefits outweigh theirrisks.
C) He thinks their risks outweigh theirbenefits.
D) He thinks their benefits and risks arebalanced.
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