高三二轮英语说明文阅读及技巧

Work sheet for reading expository articles说明文阅读理解学案Reading guideIn-class readingPassage 1①A Chinese scientist, He Jiankui of Southern University of Science and Technology, claimed ina video on Nov. 25, 2018 that he had used CRISPR-Cas9 to edit embryos for seven couples, with two twin girls resulting so far. He said his goal was to try to make the babies resistant to HIV.What's behind the creation?②As he said, the tool He Jiankui used to create the babies is called CRISPR-Cas9—a gene-editing tool that has been discovered in recent years. This relatively easy way to edit genes makes it possible to operate on DNA to supply a needed gene or disable one that is causing problems.③CRISPR is a guide molecule (分子) made of RNA, which targets a specific site on the DNA double helix (双螺旋). CRISPR is attached to Cas9, a bacterial enzyme(酶) that works as a pair of "molecular scissors" to cut the DNA at the exact point required. He Jiankui sought to disable a gene called CCR5 that forms a protein doorway that allows HIV, the virus that causes Aids, to enter a cell.④He said the gene editing occurred during the following process. First, sperm was “washed” to separate it from semen, in which HIV can hide. Next, a single sperm was placed into a single egg to create an embryo. Then the gene-editing tool was added.Is this helpful?⑤“I believe this is going to help the families and their children,” He Jiankui said. “Society will decide what to do next in terms of allowing or forbidding such science.”⑥However, many mainstream scientists think it's too unsafe to try. “If true, this experiment is monstrous,” said Julian Savulescu, a professor of practical ethics at the University of Oxford. “Gene editing is experimental and capable of causing social and ethical problems.”1. What is the purpose of the passage?2. What do the underlined "that" in paragraph 3 refer to respectively?3. What does the word “monstrous” mean in the last paragraph?4. Which of the following statement is true?A. CRISPR-Cas9 was used in the first step of the creation.B. CRISPR made of a bacterial enzyme is used to edit certain genes.C. CCR5 is a protein that allows HIV to enter a cell.D. The chosen sperm should be processed first to avoid HIV virus.5. What is the attitude of Professor Julian Savulescu mentioned in the last paragraph towards the claimed creation?6. What is the author's attitude towards the claimed creation?Passage 2①If you want to disturb the car industry, you'd better have a few billion dollars: Mom-and-pop carmakers are unlikely to beat the biggest car companies. But in agriculture, small farmers can get the best of the major players. By connecting directly with customers, and by responding quickly to changes in the markets as well as in the ecosystems (生态系统), small farmers can keep one step ahead of the big guys. As the co-founder of the National Young Farmers Coalition (NYFC, 美国青年农会) and a family farmer myself, I have a front-row seat to the innovations among small farmers that are transforming the industry.②For example, take the Quick Cut Greens Harvester, a tool developed just a couple of years ago by a young farmer, Jonathan Dysinger, in Tennessee, with a small loan from a local Slow Money group. It enables small-scale farmers to harvest 175 pounds of green vegetables per hour—a huge improvement over harvesting just a few dozen pounds by hand—suddenly making it possible for the little guys to compete with large farms of California. Before the tool came out, small farmers couldn't touch the price per pound offered by California farms. But now, with the combination of a better price point and a generally fresher product, they can stay in business.③The sustainable success of small farmers, though, won't happen without fundamental changes to the industry. One crucial factor is secure access to land. Competition from investors, developers, and established large farmers makes owning one's own land unattainable for many new farmers. From 2004 to 2013, agricultural land values doubled, and they continue to rise in many regions.④Another challenge for more than a million of the most qualified farm workers and managers isa non-existent path to citizenship — the greatest barrier to building a farm of their own. With farmers over the age of 65 outnumbering (多于) farmers younger than 35 by six to one, and with two-thirds of the nation's farmland in need of a new farmer, we must clear the path for talented people willing to grow the nation's food.⑤There are solutions that could light a path toward a more sustainable and fair farm economy, but farmers can't clumsily put them together before us. We at the NYFC need broad support as we urge Congress (国会) to increase farmland conservation, as we push for immigration reform, and as we seek policies that will ensure the success of a diverse and ambitious next generation of farms from all backgrounds. With a new farm bill to be debated in Congress, consumers must take a stand with young farmers.1. The author mentions car industry at the beginning of the passage to introduce___________.A. the progress made in car industryB. a special feature of agricultureC. a trend of development in agricultureD. the importance of investing in car industry2. What does the author want to illustrate with the example in paragraph 2?A. Loans to small local farmers are necessary.B. Technology is vital for agricultural development.C. Competition between small and big farms is fierceD. Small farmers may gain some advantages over big ones.3. What is the difficulty for those new famers?A. To gain more financial aid.B. To hire good farm managers.C. To have farms of their own.D. To win old farmers’ support.4. What should farmers do for a more sustainable and fair farm economy?A. Seek support beyond NYFC.B. Expand farmland conservation.C. Become members of NYFC.D. Invest more to improve technology.Passage 3If you could change your child’s DNA in the future to protect them against diseases, would you? It could be possible because of technology known as CRISPR-Cas, or just CRISPR.CRISPR involves a piece of RNA, a chemical messenger, designed to work on one part of DNA; it also uses an enzyme (酶) that can take unwanted genes out and put new ones in, according to The Economist. There are other ways of editing DNA, but CRISPR will do it very simply, quickly, and exactly.The uses of CRISPR could mean that cures are developed for everything from Alzheimer’s to cancer to HIV. By allowing doctors to put just the right cancer-killing genes in to a patient’s immune system, the technology could help greatly.In April scientists in China said they had tried using CRISPR to edit the genomes (基因组) of human embryos. Though the embryos would never turn into humans, this was the first time anyone had e ver tried to edit DNA from human beings. With this in mind, the US’ National Academy of Sciences plans to discuss questions about CRISPR’s ethics (伦理问题).For example, CRISPR doesn’t work properly yet. As well as cutting the DNA it is looking for, it often cuts other DNA, too. In addition, we currently seem to have too little understanding of what DNA gives people what qualities.There are also moral questions around “playing God”. Of course, medicine already stops natural things from happening —— for example, it saves people from infections. The opportunities to treat diseases make it hard to say we shouldn’t keep going.A harder question is whether it is ever right to edit human germ-line (种系) cells and make changes that are passed on to children. This is banned in 40 countries and restricted in many others. However, CRISPR means that if genes can be edited out, they can also be edited back in. It may be up to us as a society to decide when and where editing the genome is wrong.Also, according to The Economist, gene editing may mean that parents make choices that are not obviously in the best interests of their children: “Deaf parents may prefer their children to be deaf too; parents might want to make their children more intelligent at all costs.”In the end, more research is still needed to see what we can and can’t do with CRISPR. “It’s still a huge mystery how we work,” Craig Mello, a UMass Medical School biologist and Nobel Prize winner, told The Boston Globe. “We’re just trying to figure out this amazingly complicated thing we call life.”1. What is the article mainly about?A. How CRISPR was developed by scientists.B. What we can and can’t do with CRISPR.C. Chinese scientists’ experiment of using CRISPR to edit human embryos.D. The advantages of CRISPR and arguments about its ethics.2. According to the article, the technology of CRISPR ________.A. is very safe because it only cuts the DNA it is looking forB. is banned in 42 countries and restricted in many othersC. could cause parents to make unwise choices for their childrenD. could help us discover the link between DNA and the qualities it gives people3. It can be concluded from the article that CRISPR ________.A. could be helpful in the treatment of cancer and HIVB. allows scientists to edit genomes for the first timeC. is a technology that uses an enzyme to work on RNA and DNAD. has proven to be the most effective way to protect children against diseases4. What is the author’s attitude toward CRISPR?A. Supportive.B. Worried.C. Negative.D. Objective.Homework1.Review what you’ve learned and finish your work sheet.2.Summarize a guide for reading expository articles.。