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(發(fā) 現(xiàn)) 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). “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】Which is not true about the advantage of enzyme?

A.It’s able to make plastics become smaller parts.

B.It can solve the problem of the plastic pollution right now.

C.It’s used to make the plastics disappear in a rapid way.

【2】The underlined phrase “break down” in the passage probably means “________” in Chinese.

A.實(shí)驗(yàn)B.生產(chǎn)C.分解

【3】Which isn't the change they made to the natural enzyme?

A.Some amino acids were put in it.

B.The speed of plastic-eating has been improved.

C.The quality of plastic -eating remained the same.

【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 woks better than the improved one.

【5】We can’t infer from the study that________.

A.The team is able to increase the speed of the plastic -eating abilities

B.Efforts are made to increase the number of PET that the enzyme breaks down

C.Few efforts are required to the improvement of this new enzyme

A. visit B. visits

C. to visit D. to visiting

—Yes，it's easy.

A. what to use B. how to use

C. whom to use D. which to use

A. am B. is C. are D. be

— .

A. for; You’re welcome B. to; Not at all

C. you for; Excuse me D. to; Sorry

A. popular B. less popular

C. more popular D. the most popular

A. away; on B. for; about

C. off; in D. off; for

A. and B. but C. or D. So

—_________.

A .It’s right B. Sorry, I won’t do it again

C. It doesn’t matter D. I know

A. do you B. don’t you

C. is it D. isn’t it