题目内容：

    Researchers have developed paper that can be printed with UV light (紫外线)， free from the need for ink (油墨). People can clear the information away on the light-printable paper by heating it to 120°C and it can be reused more than 80 times.

The research was carried out in order to reduce the effects of paper production on deforestation (滥砍滥伐). The researchers, from Shandong University in China and the University of California, Riverside, said that the secret behind the technology is a color-changing chemical. A thin coating of the chemical can be used on usual paper and turn it into a reusable, light-printable one. Heating the paper for 10 minutes can help clear the information away more quickly.

Professor Yadong Yin, a chemistry professor at the University of California and a co-author of the study, said, “The greatest importance of our work is the development of a new technology to produce an ink-free rewritable paper that has the same feel and appearance as usual paper. Our work is believed to have great economic and environmental influences on the modem society.” Paper production has a bad influence on the environment. It’s the main cause of industrial pollution and paper thrown away by people makes up about 40% of landfills where waste is buried under the ground.

It is predicted that light-printable paper will be inexpensive in the future. The printing process is also more cost-effective than the usual one as no ink is needed. Most importantly, it can be reused many times, which greatly reduces the cost.

1.Why did researchers do the research?

A. To make more money by selling the paper. B. To save more ink and more money.

C. To make people interested in writing on the paper. D. To stop people from cutting down more trees.

2.What does the underlined word “it” refer to?

A. Usual paper. B. The chemical. C. The technology. D. Ink.

3.What can’t we know from Paragraph 3?

A. The rewritable paper looks the same as the usual paper. B. Wasted papa: is the most serious pollution.

C. The research will make a difference to our economic development. D. Our environment will be influenced by the rewritable paper.

4.What are the advantages of the rewritable paper?

a. It can be recycled many times.

b. It can help save money.

c. It is environmentally-friendly.

d. It will help save time.

A. abc B. bed C. acd D. abd