A: Good morning, doctor.

B: Good morning. What's the matter with you?

A: This morning I {#blank#}1{#/blank#} a pain in my head.

B: How are you feeling now?

A: I'm feeling {#blank#}2{#/blank#} worse.

B: Let me {#blank#}3{#/blank#} your temperature. It is nothing serious.

A: Really? But I don't feel any better now. 

B: Did you eat anything for breakfast?

A: No. I didn't feel like {#blank#}4{#/blank#} anything.

B: Well, take this medicine {#blank#}5{#/blank#} a day. You'll be all right soon.

A: OK. Thank you.  

    Until the early twentieth century, it was always unsuccessful to transfuse blood（输血） from one person to another person. Then in 1901, Karl Landsteiner, an Austrian scientist, discovered that there are four types of blood. These four blood types were named A, B, AB, and O. People have one of these four types. Blood type O is the most{#blank#}1{#/blank#} around the world because the number of the people with type O is the largest, while type AB is the least. If people with type A blood are given type B blood,  or people with type B blood are given type A blood,  they will{#blank#}2{#/blank#} die. Karl Landsteiner's research made it possible to be sure that people who need blood get the correct type.

    The study of blood didn't stop. In 1972, a Japanese doctor, Furukawa Takeji, {#blank#}3{#/blank#} another research about blood. And he came up with the idea that it was possible to tell one person's {#blank#}4{#/blank#}only by his blood type, which can help you know about the person quickly.

    The second man complained every other mile, his back pain got more and more  {#blank#}1{#/blank#}. On the Sth mile, he couldn't stand it any more and fell down on the grass. "My back is hurting me so badly. I can't go any{#blank#}2{#/blank#}because of the pain and it is al because we had to carry that silly woman across the river!" Out of{#blank#}3{#/blank#}, he asked. "why aren't you complaining about it? Doesn't your back hurt?"

    "Of course not, "the first man replied, "You have been carrying the woman since we left the river bank. But I set her down five miles ago."

    We are often like that second man who can't release complaining and pain of{#blank#}4{#/blank#}. Years later, we still carry the burdens, worn out, and can't go any further.