单选题
A bite of a cookie containing peanuts could cause the airway to constrict fatally. Sharing a toy with another child who had earlier eaten a peanut butter and jelly sandwich could raise a case of hives. A peanut butter cup dropped in a Halloween bag could contaminate the rest of the treats, posing an unknown risk. These are the scenarios that "make your bone marrow turn cold" according to L. Val Giddings, vice president for food and agriculture of the Biotechnology Industry Organization. Besides representing the policy interests of food biotech companies in Washington, D. C., Giddings is the father of a four-year-old boy with a severe peanut allergy. Peanuts are only one of the most allergenic foods; estimates of the number of people who experience a reaction to the beans hover around 2 percent of the population. Giddings says that peanuts are only one of several foods that biotechnologists are altering genetically in an attempt to eliminate the proteins that do great harm to some people's immune systems. Although soy allergies do not usually cause life-threatening reactions, the scientists are also targeting soybeans, which can be found in two thirds of all manufactured food, making the supermarket a minefield for people allergic to soy. Biotechnologists are focusing on wheat, too, and might soon expand their research to the rest of the "big eight" allergy-inducing foods: tree nuts, milk, eggs, shellfish and fish. Last September, for example, Anthony J. Kinney, a crop genetics researcher at DuPont Experimental Station in Wilmington, Del., and his colleagues reported using a technique called RNA interference (RNAi) to silence the genes that encode p34, a protein responsible for causing 65 percent of all soybean allergies. RNAi exploits the mechanism that cells use to protect themselves against foreign genetic material; it causes a cell to destroy RNA transcribed from a given gene, effectively turning off the gene. Whether the public will accept food genetically modified to be low-allergen is still unknown. Courtney Chabot Dreyer, a spokesperson for Pioneer Hi-Bred International, a subsidiary of DuPont, says that the company will conduct studies to determine whether a promising market exists for low allergen soy before developing the seeds for sale to farmers. She estimates that Pioneer Hi-Bred is seven years away from commercializing the altered soybeans. Doug Gurian-Sherman, scientific director of the biotechnology project at the Center for Science in the Public Interest—a group that has advocated enhanced Food and Drug Administration oversight for genetically modified foods—comments that his organization would not oppose low-allergen foods if they prove to be safe. But he wonders about "identity preservation" a term used in the food industry to describe the deliberate separation of genetically engineered and no nengineered products. A batch of nonengineered peanuts or soybeans might contaminate machinery reserved for low-allergen versions, he suggests, reducing the benefit of the gene-altered food. Such issues of identity preservation could make low-allergen genetically modified foods too costly to produce, Chabot Dreyer admits. But, she says, "it's still too early to see if that's true. /
单选题According to the text, foods have been genetically altered to______. [A] taste more delicious [B] to cure people's ineffectiveness in immune system [C] to promote sales of peanut [D] to lower the chance to get allergy
单选题 What can be inferred about genetically modified foods from the text? [A] People do not accept any genetically modified foods. [B] All genetically modified foods will be of benefit to people's health. [C] Genetically modified foods still have a long way to go. [D] Genetically modified foods will soon be sold in supermarkets.
单选题According to the text, which of the following statements is true? [A] Genetically modified foods have been supervised by the authority. [B] Genetically modified foods have proved to be safe. [C] The nonengineered foods absolutely can be contaminated by the engineered foods. [D] The engineered foods are immediately profitable for the food companies.
【正确答案】
A
【答案解析】[考点] 推理判断 [解析]通读全文，我们把本题定位在最后两段的议论上。文章在最后一段第一句话提到“公共利益科学中心一贯要求食品与药品管理局加大对转基因食品的监控”，其中enhanced(加大)一词就说明目前食品与药品管理局对转基因食品有监控措施，只不过公共利益科学中心认为这种监控力度不够，所以选项A是正确答案。 [干扰项分析] 文章只是提到了转基因食品面临的挑战，并没有明确指出转基因食品被证明安全或不安全，选项B属于文章没有提到的内容，因此可以排除。虽然前面提到了转基因食品可以降低食品过敏几率，但并不足以说明转基因食品被证明是安全的。文章最后一段所谓“身份保留问题”实际上就是关于非转基因食品是否会污染转基因食品的讨论。关于这一问题有两种观点，第一种观点很容易看出来，Doug Gurian-Sherman认为会存在污染，第二种观点就隐晦得多，Chabot Dreyer。认为这个问题也许会增加成本，但最后一句话至关重要，“it’s still too early to see if that’s true”，其中it就是指是否污染的问题，显然后者对污染与否持怀疑态度。换句话说，对于这个问题人们还没有定论，所以选项C可以排除。至于选项D，很多考生都容易想到新技术带来利益是很正常的，但千万不要忘了immediately(立刻)这个单词。文章第五段提到要卖转基因种子给农民至少要等七年，言下之意，在搞清楚市场潜力之前，转基因食品不会立刻上市，因此也就不会立刻带来利益，故排除D项。
单选题From the text, we can know that RNAi______. [A] can deprive cells of certain mechanism [B] can protect cells against foreign genetic material [C] can be effective on 34 kinds of genes [D] can cause soybean allergies