By using fibers from seemingly delicate fruits such as bananas and pineapples, the scientists claim that they can strengthen new plastics, making them not only stronger and lighter, but more sustainable (可持续的) as well.

　　"They (the new plastics) are light, but very strong - 30 percent lighter and three to four times stronger than old plastics，" research leader Alcides Leao from Sao Paulo State University in Brazil told the American Chemical Society. Some of the fibers can be as strong as Kevlar, a super­strong material used to make bulletproof vests. Besides, the plastics are also more resistant to damage from heat, water, oxygen and even spilled gasoline.

　　Cellulose (纤维素) is the main component (成分) of wood and has been used for centuries to make paper. Recently scientists have discovered that intensive (密集的) processing of wood releases tiny or nano­cellulose fibers, so tiny that 50，000 could fit across the width of a single human hair. When mixed with other raw materials, these nano­cellulose fibers can make plastics stronger.

　　According to Leao, pineapple leaves and stems (茎), and a plant related to the pineapple in South America, called curaua, rather than wood may be the most promising source for nano­cellulose. To create the plastics, researchers put the leaves and stems of pineapples and other plants into a device similar to a pressure cooker. Then they added certain chemicals and heated the mixture over several cycles, producing a powder that was then added to the plastics.

　　The process is costly, but it takes just 1 pound of nano­cellulose to produce 100 pounds of super­strong, light­weight plastics, Leao pointed out.

　　Some car makers have already tested these nano­cellulose plastics and scientists have predicted the plastics would be in use within two years, mainly for bodies of cars.

　　1．The underlined word "reinforce" in the first paragraph is closest in meaning to "________"．

　　A．take the place of

　　B．make something stronger

　　C．increase the percentage of

　　D．get rid of

　　2．Which of the following statements about the nano­sized fruit fiber is TRUE?

　　A．It is used to make bulletproof vests.

　　B．It is used to replace steel and aluminum automotive parts.

　　C．It can resist damage from heat, water or oxygen.

　　D．Leao thinks it is better than nano­cellulose from wood.

　　3．According to the article, which of the following is the correct order that researchers produced super­strong, lightweight plastics?

　　a．put pineapple leaves and stems into a device similar to a pressure cooker

　　b．a powder is formed

c．add some powders to the plastics