A
American researchers say drinking tea may help strengthen the body's defense system against infection．Doctors at Brigham and Women's Hospital in Boston， Massachusetts， did the study． The team studied a chemical found in black， green， oolong and pekoe tea． This chemical is an amino acid called L-theanine． The scientists say it may increase the strength of gamma delta T cells． That's the letter T， not the drink． Gamma delta T cells are part of the body's defense．
First， the researchers mixed some of these cells with antigens found in the amino acid． Antigens help the body react to infection． Then the scientists added some bacteria． Within twenty-four hours， the cells produced a lot of interferon， a substance that fights infection． Cells not mixed with the antigens did not produce interferon．
In the second part of the study， eleven people drank five to six cups of black tea every day． Ten other people drank the same amount of instant coffee． That is dried coffee mixed with hot water．
Two weeks later， and again two weeks after that， the researchers tested the blood of all twenty-one people． They also looked at what happened when they added bacteria to the blood cells． They found that the tea drinkers produced five times more interferon after they started drinking tea． The coffee drinkers did not produce interferon．
Doctor Jack Bukowski led the study． He says the antigens added to the gamma delta T cells were responsible for the increased reaction to the bacteria． He says that the study also showed that the cells were able to remember the bacteria and fight them again the next time．
Earlier research already has found that tea can help prevent heart disease and cancer． Doctor Bukowski says the new study must be repeated by more people． "If the findings prove to be true，" he says， "then tea drinking might also help protect against bacterial infections．" He says the amino acid L-theanine could be removed from the tea and used as a drug to strengthen the body's defenses．
1. We may know from the text that ______ can be found in different kinds of tea．
A. L-theanine B. Gamma delta T cells
C. interferon D. bacteria
2. Tea may help strengthen the body's defense system because it helps ______ ．
A. to add some bacteria to the blood cells
B. the body to produce more gamma delta T cells
C. the body to produce more interferon
D. to mix antigens with some of the cells in the body
3. According to Dr Bukowski， ______ ．
A. the findings of the study have already proved to be true
B. further study is needed to prove the findings true
C. he has taken some amino acid L-theanine from tea and made a drug with it
D. he is not sure whether tea help prevent heart disease and cancer
【答案】1. A 2. C 3. B
【解析】
这是一篇说明文。主要讲
是喝茶可以增强身体对感染的抵御能量力，因为它可以使身体制造出更多的干扰素．
【1题详解】
细节理解题。从第一段的句子：The team studied a chemical found in black，green，oolong and pekoe tea．This chemical is an amino acid called L-theanine．可知，不同的茶里面都有的物质是L-theanine，故选A。
【2题详解】
细节理解题。根据第二段的the researchers mixed some of these cells with antigens found in the amino acid（氨基酸）．Antigens help the body react to infection 可知茶有助于加强身体的免疫力因为它可以使身体制造出更多的干扰素，故选C。
【3题详解】
细节理解题。根据最后一段的Doctor Bukowski says the new study must be repeated by more people．可知Doctor Bukowski 认为要证明这个发现是真的，还需要更多的研究，故选B。
