整理雅思阅读测试卷.docx

整理雅思阅读测试卷.docx雅思阅读测试卷
READING PASSAGE 1
You should spend about 20 minutes on Questions 1-14 which are based on Reading Passage 1 on hers have used both yeast and bacteria as hosts to grow the raw material, which they have spun into fibres. Robert Dorsch, DuPont's director of biochemical development, says the globules of protein, parable with marbles in an egg, are harvested and processed. 〃We break open the bacteria, separate out the globules of protein and use them as the raw starting material. With yeast, the gene system can be designed so that the material excretes the protein outside the yeast for better access, " he says.
F 〃The bacteria and the yeast produce the same protein,
equivalent to that which the spider uses in the drag lines of the web. The spider mixes the protein into a water-based solution and then spins it into a solid fibre in one go. Since we are not as clever as the spider and we are not using such sophisticated organisms, we substituted manmade approaches and dissolved the protein in chemical solvents, which are then spun to push the material through small holes to form the solid fibre."
G Researchers at DuPont say they envisage many possible uses for
a new biosilk material. They say that earthquake-resistant suspension bridges hung from cables of synthetic spider silk fibres may be e a reality. Stronger ropes, safer seat belts, shoe soles that do not wear out s