21、第一篇 Types of Blood 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. Howev er, special care must be taken in selecting new blood for you. If the blood is t oo 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 ind icate a person’s blood type. Everybody is born with one of these four types of b lood. Blood type, like hair color and height, is inherited from parents. Because of substances contained in each type, the four groups must be transf used carefully. Basically, A and B cannot be mixed. A and B cannot receive AB, b ut AB may receive A or B. O can give to any other group; hence, it is often call ed the universal donor. For the opposite reason, AB is sometimes called the univ ersal recipient. However, because so many reactions can occur in transfusions, p atients usually receive only salt or plasma ( liquid ) 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 percenta ges. For example, some American Indian groups have nearly 100 percent type O. If a patient can receive type A blood,____
A.he must have type A blood.
B.he can also receive type AB blood.
C.he can’t have type B blood.
D.he can’t have type AB blood.

22、(同21题)The word Transfusion" is closest in meaning to____

A.transfer.
B.check.
C.treatment.
D.mixture.

23、(同21题)If you need a transfusion, the best and safest blood for you is____

A.type AB.
B.type O .
C.exactly the same type as yours.
D.a mixture of salt and plasma.

24、(同21题)According to the passage, the third most common blood type for Europeans is____

A.A..
B.B.
C.AB.
D.O.

25、(同21题)The passage is most probably written for____

A.the general reader.
B.the medical student.
C.the blood expert.
D.people badly injured in a car accident.