1、You have been badly injured in a car accident.It is necessary to give you a blood transfusion because you lost a great deal of blood in the accident.However, special care must be taken in selecting new blood for you.If the blood is too different from your own, the transfusion could kill you.

　　There are four basic types of blood; A, B, AB and O.A simple test can indicate a person's blood type.Everybody is born with one of these four types of blood.Blood type, like hair color and height, is inherited from parents.

　　Because of substances contained in each type, the four groups must be trans fused carefully.Basically, A and B cannot be mixed.A and B cannot receive AB, but AB may receive A or B.O can give to any other group, hence it is often called the universal donor.For the opposite reason, AB sometimes called the universal recipient.However, because so many reactions can occur in transfusions, patients usually receive only salt or plasma until their blood can be matched as exactly as possible in the blood bank of a hospital.In this way, it is possible to avoid any bad reactions to the transfusion.

　　There is a relationship between your blood type and your nationality.Among Europeans and people of European ancestry, about 42 percent have type A while 45 percent have type O.The rarest is type AB.Other races have different percentages.For example, some American Indian groups have nearly 100 percent type O.

　　28[单选题]A good title for this passage is _____.

　　A.Getting Blood arid Plasma

　　B.Special Blood and Colors

　　C.Human Blood Types

　　D.The Blood Bank of a Hospital

　　[答案]C

　　[解析]本文讲的就是人的血型。

　　29[单选题]If you need a transfusion, the best and safest blood for you is _____.

　　A.type AB

　　B.exactly the same type as yours

　　C.a mixture of salt, plasma and type O

　　D.type A

　　[答案]B

　　[解析]参见第二段。

　　30[单选题]The word “hence”in line 10 means _____.

　　A.always

　　B.often

　　C.therefore

　　D.seldom

　　[答案]C

　　[解析]通过上下文可知，hence这里就是“因此”的意思。

　　31[单选题]People with type A blood can receive _____.

　　A.AB

　　B.B

　　C.O

　　D.None of the above

　　[答案]C

　　[解析]根据句子“Basically, A and B cannot be mixed.A and B cannot receive AB”可以推论出，A型可以接受A型和O型的血。