17．When you cut your skin，you bleed（流血）．If a person loses a lot of blood，he will become ill and may die．Blood is very important．People have always known that．At one time，some people even drank blood to make them strong!
When doctors understand how blood goes around inside the body，they try ways of giving blood to people who need it．They take blood from the healthy people and give it to people who need it．This is called"blood transfusion"．The blood goes from the arm of the healthy person into the arm of the sick person．
But there are two problems．First，it does not always work．Sometimes people die when they have blood transfusion．Later，doctors find that we do not all have the same kind of blood．There are four groups-O，A，B and AB．We all have blood of one of these groups．They also find that they can give any kind of blood to people of group AB．But they find that they must give A-group blood to A-group people and B-group blood to B-group people．I have O-group blood and the doctor told me that I could give blood to anyone else safely．
There is another problem．To give blood of the right kind，doctors have to find a person of the right blood group．Often they can not find a person in time．If they have a way to keep the blood until someone needs it，they can always have the right kind of blood．At first they find they can keep it in bottles for fifteen to twenty days．They do this by making it very cold．Then they find how to keep it longer．In the end they find a way of keeping blood for a very long time．
We call a place where we keep money a"bank"．We call a place where we keep blood a"blood bank"．One day，when you grow up，you may decide to give blood to a"blood bank"．In this way you may stop someone from dying．Or perhaps one day you may become ill．You may need blood．The"blood ban"will give it to you．
70．From the passage，we learn that sometimes people die when they have blood transfusions because they．C
A．a(chǎn)re unhealthy people
B．have lost a lot of blood
C．a(chǎn)re not given the right kind of blood
D．a(chǎn)re AB-group people
71．Which of the following is true？B
A．Doctors can give any kind of blood to the writer．
B．The writer can give blood to B-group people．
C．The writer has never had a blood transfusion．
D．The writer has the same kind of blood as his father．
72．People set up the"blood bank"so that they can．A
A．give the right kind of blood to the people who need it in time
B．keep different groups of blood as much as possible
C．make it easier to sell or buy blood
D．keep blood for more than twenty hundred years
73．The writer doesn't talk aboutCin the passage．
A．how important blood is to us
B．the four groups of blood
C．where the blood bank is
D．what"blood transfusion"is．
分析 試題分析：這篇短文主要講述血在我們的生命中是最重要的東西，人失血太多有可能會失去生命．在這種情況下，就會到醫(yī)院輸血．但是輸血時還要先匹配血型，如果血型不符，被輸血人還是會有死亡的風險．為了讓失血過多的人可以在短時間內(nèi)獲得足夠的血液，建立了血庫，用于保存大量的血液供病人使用．獻血既可以救人又可以在自己需要時使用，所以獻血對自己是有好處的．
解答 70．C，推理判斷題，文中提到"Sometimes people die when they have blood transfusion．Later，doctors find that we do not all have the same kind of blood"有的時候人們接受輸血后就會死亡，因為血型分為四種，四種之間有的不能混用，否則會致死，由此確定選擇C．
71．B，推理判斷題，文中提到"I have O-group blood and the doctor told me that I could give blood to anyone else safely"醫(yī)生告訴我我是O型血，可以給任何人輸血，由此確定選擇B．
72．A，推理判斷題，文中提到"In this way you may stop someone from dying"通過這種方式或許可以阻止失血過多的人死亡，由此確定血庫的存在只是確保失血過多的人可以及時的獲得血液，由此確定選擇A．
73．C，推理判斷題，在最后一段中"We call a place where we keep blood a"blood bank"存放血液的地方叫做血庫，但并沒有指明血庫在哪，由此確定選擇C．
點評 對于判斷對錯題，一定要記得首先通讀全文，了解文章大意，然后再根據(jù)文章關(guān)鍵詞，關(guān)鍵句，掌握細節(jié)問題，并進行推理判斷，再去回答具體的問題．
