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.

    Li Lin said goodbye to his sister Li Wei. Li Lin said that he would {#blank#}1{#/blank#} his family, and Li Wei told him to {#blank#}2{#/blank#} care. When Li Lin got on the train, he saw an elderly man was {#blank#}3{#/blank#} in his seat. He politely called the elderly man sir and said he was {#blank#}4{#/blank#} that the elderly man was sitting in his seat. The ticket {#blank#}5{#/blank#} arrived and explains the mistake. Li Lin {#blank#}6{#/blank#} offered to change seats with the elderly man, and {#blank#}7{#/blank#} to Car 9. There he saw his friend Wen Peng, {#blank#}8{#/blank#} was happy to see him and told him to took {#blank#}9{#/blank#} his jacket, sat down and made {#blank#}10{#/blank#} comfortable.

A: It's hot today.

B: Yes, it is really hot. I want to eat ice-cream.

A: I think it is bad for your {#blank#}1{#/blank#}.

B: But 1 really want to eat something cool.

A: What about eating tomatoes with {#blank#}2{#/blank#}? I can make it.

B: Good! What do we need?

A: Three tomatoes and five {#blank#}3{#/blank#} of sugar.

B: OK ... I'm coming. What should we do first?

A: Wash the tomatoes and cut them into {#blank#}4{#/blank#}.

B: What's next?

A: Put them on a plate and {#blank#}5{#/blank#} the sugar.

B: Is that all?

A: Yes. You can enjoy them now.