《2025年同步练习册山东人民出版社高中英语选择性必修第一册外研版》

C
Besides healthy soil, all plants need water. This makes it hard to grow plants where it’s dry. But researchers in Texas may have found a way to keep plants from dying of thirst at dry sites. They developed a soil additive. When mixed into the ground, it will absorb water from the air to share with plants.
Their invention is a super-moisture-absorbent gel (凝胶), or SMAG. It absorbs water from the air during the night. When the sun warms it the next day, the gel releases its accumulated moisture (水分) into the root zone of the plants.
The gel-based material “can be used as a soil enhancer (增强剂), as well as alternative soil in greenhouses for crop planting,” said Guihua Yu. He’s an engineer at the University of Texas-Austin. He led the team that developed the gel. Depending on the plants being grown, he says, this material could be “directly mixed with soil or fertilizer (肥料) at certain amounts.”
To test the soil additive, Yu grew radishes (萝卜) on the roof of buildings at the school. During an experiment, they compared radishes grown in sandy soil alone with radishes grown in sandy soil that had been mixed with the gel. The gel-treated soil lost about 60 percent of the water that it had started with about a month earlier. In contrast, the untreated soil lost 80 percent of its water in just one week.
Jeff Hattey is a soil scientist who works at the Ohio State University in Columbus. He says similar additives have been used in potting soil for many years. “When you buy potting soil at the store,” he says, “you may see labels that say, ‘slow release fertilizer’.” The gel works in a similar way.
Yu believes future studies will help his team understand if the gel could be used for larger, outdoor fields. If it can, the moisture collected by the gel-treated soil could allow crops to be grown in drier climates, where irrigation (灌溉) is not practical.
Fortunately, the gel is not poisonous, Yu says. So it shouldn’t hurt the bacteria or worms that are needed to keep soil healthy for growing things. The gel also poses no risks if it washes into lakes or streams. Some special bacteria may even help the gel safely break down, he adds. The research team hopes to confirm that in the near future.
28. What is Paragraph 2 mainly about?
A. The main features of the gel.
B. The major advantages of the gel.
C. The working theory of the gel.
D. The operating conditions of the gel.
29. What’s the feature of the gel-based material?
A. It’s cheap and cost-effective.
B. It’s lasting in tough conditions.
C. It’s easily available for farmers.
D. It’s convenient and simple to use.
30. What’s the finding of Yu’s experiment?
A. The sandy soil loses water very quickly.
B. The radishes need a lot of water to grow.
C. The gel functions well in providing water.
D. The radishes can survive in dry soil for a month.
31. What is Yu’s attitude towards the gel?
A. Objective.
B. Optimistic.
C. Concerned.
D. Doubtful.

答案： 28.C 段落大意题。根据第二段内容可知，第二段主要介绍了凝胶的工作原理。故选C。
29.D 细节理解题。根据第三段最后一句可知，根据种植的植物，这种材料可以直接与土壤或肥料进行一定量的混合。由此可知，凝胶材料的特点是它使用方便、简单。故选D。
30.C 细节理解题。根据第四段最后两句可知，经过凝胶处理的土壤失去了一个月前开始时的60%的水分。相比之下，未经处理的土壤在一周内失去了80%的水分。由此可知，这种凝胶能很好地供应水分。故选C。
31.B 观点态度题。根据最后一段的内容可知，凝胶不会伤害保持土壤健康生长所需的细菌或蠕虫。这种凝胶如果被冲进湖泊或溪流也不会有任何风险。由此判断出，他对凝胶的态度是乐观的。故选B。