Question

7．Harmful microbes like bacteris，viruses and other germs are pathogens．They may enter your bodies and make you ill．The immune system is the body's defence system that protects you from illness and disease caused by the pathogens．
The immune system is made up of non-specialized defences such as skin，tears and the acidic juice produced by the stomach，keeping you from the pathogens．It also has some highly specializde defences，which are different kinds of immune cells，grouped into phagocytes and lymphocytes．Phagocytes are a type of white blood cell．They are swimming around in your blood stream，always on the lookout for antigens-the pathogens that have entered your bodies．Whenever they see one，ther will eat it．However，some antigens are hard to find and kill．Then lymphocytes，which are also white blood cells and the main types are B cells，T helper cells and T killer cells，Will be the killers of the sncaky antigens．
B cells，T helper and T killer cells work together to find and kill these antigens．B cells produce substances，called antibodies，which stick to the antigen．When that happens，it will tell the T helper cells to come over and either：1．help the B cells kill the antigen，or 2．call the phagocytes or T killer cells to move in for the kill．Once a B cell or a T cell attacks an antigen，they create cells to"remember"it．Those"memory cells"hang out in your blood if they see the same antigen again，they quickly recognize，it so your immune system can act faster at killing it．
The immune system is more powerful than you probably imagine．Scientists from the University of Pennsylvania recently took immune cells from three patients with leukemia，then genetically cheanged them into"serial Keller"cells to attack cancer cells．The study was small but the results were groundbraking．The modified immune cells increascd at least 1，000 times in the body and killed all the cancer cells．Therefore，more"memory cells"were created．
  The immune system can be developed．Eating lean protein food （beef，beans ）and food rich in vitamins A，C，and E（sweet potatoes，carrots ），taking a 30-minute walk every day and reducing your stress levels，etc．will help you achieve it．

37．What can the immune system do？B
A．Keep you from antibodies．
B．Protect you against antigens．
C．Make your bodies werk and sick．
D．Help microbes enter your bodies
38．How are the sneaky antigens found and killed？A
A．Phagocytes，B，T helper and T killer cells work together
B．Skin，tears，acidic juice and immune cells work together
C．B cells create"memory cells"to swim around in the blood
D．B cells produce antibodies to tell T helper and T killer cells
39．What does the underlined word"it"in the last paragraph refer to？A
A．The immune system can be made more powerful
B．Less antigens can be killed by the immune system
C．White blood cells act less quickly in the immune system
D．The immune system can be changed into the"serial killer"
40．This article is mainly aboutD．
A．the types of white blood cells
B．a research report about human healeh
C．the cause of illness and discase
D．an introduction to the immune system．

Answer 1

分析 细菌、病毒以及其他的微生物等有害的细菌都是病原体．他们可以侵入人体并引起疾病．我们身体里面的免疫系统是我们身体里的防御系统，保护我们免受这些病原体引起的疾病的侵害．我们的免疫系统包括人体的皮肤、眼泪以及胃里产生的酸性物质等．同时，它还包括由不同的免疫细胞组成的高级识别防御系统．这个系统由噬菌细胞和淋巴细胞组成．噬菌细胞是一种白细胞．它们游走在我们的血管中，随时警惕抗原---那些侵入我们人体的病原体．只要发现一个，它们就会消灭掉一个．然而，有些抗原很难被发现并清除．此时，淋巴细胞就会出马来歼灭这些"狡猾的敌人"．这一类淋巴细胞也是白细胞的一种，但主要是由B细胞，T辅助细胞以及杀伤性T细胞组成．
B细胞，T辅助细胞以及杀伤性T细胞共同协作来歼灭外敌．B细胞产生一种称为"抗体"的物质，并黏着于抗原上．然后，它会释放出信号，请T辅助细胞共同灭敌．它们通过以下两种方式：要么由T辅助细胞协助B细胞杀灭抗原，要么由T辅助细胞或噬菌细胞浸入抗原体，并将之歼灭．一旦B细胞或T辅助细胞灭敌成功，它们就会产生一种"记忆细胞"．这些记忆细胞会游走在血液里．一旦遇上同一种抗原，它们就会很快识别它．此时，我们身体里的免疫系统能够更快地发挥作用，杀灭抗原．
我们的免疫系统或许比我们想象的要强大．近期，来自宾夕法尼亚大学的科学家提取了三名白血病病人的免疫细胞，然后通过基因技术把他们转变成抗癌细胞．这项研究虽小，但结果是开创性的．重组后的免疫细胞在身体内繁殖了至少一千倍，并杀灭了所有癌细胞，从而产生了更多的"记忆细胞"．
人们可以进一步发展我们的免疫系统．食用牛肉、豆类等高蛋白食物和番薯、胡萝卜等高维生素A、C和E的食物，每天散步三十分钟以及减少我们的压力等方式都可以达到这个效果．

解答 37．B．细节理解题．根据第一段The immune system is the body's defence system that protects you from illness and disease caused by the pathogens．我们身体里面的免疫系统是我们身体里的防御系统，保护我们免受这些病原体引起的疾病的侵害．故选B．
38．A．细节理解题．根据第二段Then lymphocytes，which are also white blood cells and the main types are B cells，T helper cells and T killer cells，Will be the killers of the sncaky antigens．淋巴细胞就会出马来歼灭这些"狡猾的敌人"．这一类淋巴细胞也是白细胞的一种，但主要是由B细胞，T辅助细胞以及杀伤性T细胞组成．故选A．
39．A．词义理解题．根据最后一段The immune system can be developed人们可以进一步发展我们的免疫系统，可知这里的it替代的是The immune system can be made more powerful，故答案是A．
40．D．主旨大意题．根据第一段The immune system is the body's defence system that protects you from illness and disease caused by the pathogens．我们身体里面的免疫系统是我们身体里的防御系统，保护我们免受这些病原体引起的疾病的侵害．第二段The immune system is made up of non-specialized defences such as skin，tears and the acidic juice produced by the stomach，keeping you from the pathogens我们的免疫系统包括人体的皮肤、眼泪以及胃里产生的酸性物质等，最后The immune system can be developed人们可以进一步发展我们的免疫系统，本文主要是介绍免疫系统，故答案是D．

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