题目内容：

Do you know blood types?

Special care must be taken in selecting new blood for a badly injured person, who would be killed by the transfusion (输血) if the blood is too different from his own.

There are four basic types of blood A. B. A B. and O. Blood type, like hair and height, comes from parents. Basically, A and B can not be mixed. AB, sometimes called the universal recipient (万能受血者), may receive A or B,. O type, often called the universal donor (万能输血者), gives his blood to any other group. Patients usually receive nothing, but salt or plasma (血浆) until their blood can be matched as exactly as possible in the blood bank of a hospital. There is a relationship between your blood type and your nationality (国籍). Among Europeans, about 42 % have type A while 45 % have type O. The fewest is the type B.

1.Which of the following show the correct relationship in blood transfusion ("→"means giving blood to...)?

   

A．                 B．                 C．                 D．

2.Usually person who has been injured and lost too much blood should be given a blood transfusion______.

A．after he receives salt and plasma　          B．before he feels uncomfortable

C．when the new blood fits his body　         D．as soon as accident happens

3.From this passage we can know that among Europeans ______ 13 % have the type B.

A. about 　　B. no more than 　　C. less than 　　D. at most