Unit 1 单元话题阅读理解练习-2023-2024学年高二英语选择性必修第二册单元重难点易错题精练（人教版2019）.docxVIP

第 第 PAGE 1 页 共 NUMPAGES 18 页 第 第 PAGE 2 页 共 NUMPAGES 18 页 Unit 1 Science and Scientists 单元话题阅读理解专项练习 (名校最新真题) （2022·广西·南宁三中高二期中）To solve the problem of tiny plastics polluting waterways, chemists in the Czech Republic are thinking small. Their brainchild is a new microrobot which is no bigger than the tip of a sharpened pencil. When sunlight hits them, they produce chemical reactions that push them through water in a specific direction. When they find a piece of plastic, they stick to it and start to break it down. Chemist Martin Pumera at the Czech University led the project. A decade ago, he chose to focus on the problem posed by microplastics. They’re everywhere—from the bottom of the ocean to air blowing onto ice atop mountains. They’ve turned up in drinking water. Some studies estimate that billions of pieces of plastic end up in the world’s waters. The plastic has many sources, from shopping bags to washing and cleaning wipes. In lab experiments, the star-shaped swimmers stuck onto each of four different types of plastic. And after a week exposed to light, the robots had reduced the weight of the plastics. It wasn’t much—only by percent. But that was an indication that they were breaking the plastic down. They also caused the surface of the plastic to change from smooth to rough. That’s another sign that the robots were degrading (分解) it. The new study is a proof of concept type. That means it shows something can be done successfully. In fact, Pumera says they still have a long way to go. There are many types of plastics. And even these microrobots are unlikely to succeed in degrading them all. The researchers also have not yet shown how safe this system is for the environment, although Pumera says that’s their next goal. The first real-world test will be in a wastewater-treatment plant. “Indeed,” says one researcher. “We’ll need a lot of testing to show that they’re safe in open waterways, such as at sea.” 1．What does the underlined word “brain