题目内容：

In 2016, a team of Japanese scientists found bacteria capable of breaking down and “eating” one of the world’s most popular plastics-polyethylene terephthalate(PET). It was valued as a potential breakthrough at the time. But a new discovery came as a team of British scientists examined an enzyme(酶) produced by the Japanese bacteria to find out more about its structure. While operating the structure to better understand how it worked, they accidentally created the changed enzyme that’s even more efficient at breaking down plastic bottles.

The researchers are now working to further improve the enzyme so it can be used on an industrial scale. It’s possible that within the next few years there could be an industrially possible process for turning PET into other substances so it can be recycled.

The ability to scale up the process will be important. Plastic pollution is fast becoming one of the biggest environmental issues of our time. More than 1 million plastic bottles are bought around the world every minute. Most of these bottles are made from PET，which can take up to00 years to biodegrade(生物降解), and many are left in the oceans. Over half of global PET waste is not collected for recycling and only 7 percent of bottles are recycled into new bottles.

Some scientists say the breakthrough, though promising, is nowhere near enough to solve our pollution crisis. These enzymes are not abundantly present in nature. So you would need to produce the enzyme first, then add it to the PET plastic to degrade it.”This is likely to be a slow process. If you have gone through the trouble of collecting the PET waste, then there are clearly far better ways to recycle it or burn it for energy,” said Wim, head of the Industrial Biotechnology Center. He suggested the use of commercially available biodegradable bioplastics would still be a better bet.

1.What unexpected discovery did the British scientists make?

A. An effective way to deal with plastic waste.

B. A potential solution in collecting PET waste.

C. The way to understand the structure of enzyme better.

D. The real value of the discovery by Japanese scientists.

2.What does the underlined phrase “the process” in Paragraph 3 actually refer to?

A. The process to find the enzyme.

B. The process to make more plastics.

C. The process to reduce the PET waste.

D. The process to produce kind of new PET.

3.What is the problem about recycling the PET waste?

A. Large quantities of plastic bottles are used.

B. Ocean plastic waste is harder to biodegrade

C. Most of the PET waste is left without treatment.

D. Most of the plastic products are made from PET.

4.What can be concluded from the last paragraph?

A. The enzyme does not exist in nature.

B. The enzyme has helped to solve the plastic problems.

C. Burning plastic waste for energy is now the best way to rid it.

D. We have a long way to go to use the enzyme to recycle PET waste.