1. (2018·重庆) 阅读下列材料，从A、B、C、D四个选项中选出最佳答案。C
    Scientists in Britain and the United States have made a new kind of enzyme (酵素) that eats plastics (塑料). With its help, plastics can be turned into smaller parts and go away quickly. Scientists believe that, in the future, it could solve the problem of plastic pollution.
    The enzyme is able to break down PET, a form of plastic. PET was first made in the 1940s and is now widely used to make plastic bottles. It can remain in the environment for many years and pollute large areas of land and water. So it has always been a headache to deal with the waste from PET and other plastics.
    The researchers made the discovery (发现) while examining the structure of a natural enzyme in Japan. They found that the natural enzyme was helping to break down PET plastics. So, they decided to make small changes to the enzyme by adding some amino acids (氨基酸). It made the natural enzyme's plastic-eating abilities work faster and better.
    John McGeehan, one of the lead researchers, said, “We've made an improved enzyme. It's better than the natural one. And we are trying to make more improvements to it.” He went on, “The enzyme is not harmful to humans or animals, and it is friendly to the environment. So we are considering putting it into wider use.”
    The team is now trying to make the enzyme break down PET in large quantities (大量地). “We'll see that the plastic pollution may be stopped with this technology. However, there is still a long way to go,” John McGeehan added.

1. （1） According to the scientists, the enzyme may solve the problem of _______ pollution.

   A . air B . water C . light D . plastic
3. （2） The underlined phrase “break down” in the passage probably means “______” in Chinese.

   A . 实验 B . 生产 C . 发明 D . 分解
5. （3） Researchers discovered that a natural enzyme helped eat plastics _______.

   A . in Britain B . in the US C . in Japan D . in China
7. （4） Which of the following is TRUE according to the passage?

   A . The scientists are still trying to improve the enzyme. B . The enzyme will pollute large areas of land and water. C . The natural enzyme works better than the improved one. D . The natural enzyme is harmful to humans and animals.