While we are still children ,most of us live at home with our parents, more or less peacefully . But as we become teenagers , things change ,and we begin to grow apart from our parents . This means we are almost ready to leave the house where we grew up and make a new home of our own .
All humans must do this ,but they don’t all do it in the same way . If ,for instance ,you belong to a primitive tribe (原始部落) ，then as you grew up ,you’d learn the skills you needed as an adult---how to catch fish ,how to keep the house and look after children . You would be ready to marry in your early teens and you would build a house and live near your family in the village.
This seems a very old way of life , but it is what humans have been used to through hundreds of years. And it is what we are still used to in the 21st century ,for man hasn’t changed in the short time since he became civilized(文明的). But could you leave home and look after yourself during the teen years ? Most people would not do very well . Why ? Because although man hasn’t changed very much , the society he lives in has changed greatly ,which means that we have to learn more and more before we are ready to leave our parents’ shelter( 居所 ) and live alone .
However ,sometimes it is very frustrating to live at parents’ home . Parents can be very upset about late nights ,criticizing friends and always saying that we are noisy and dirty . But we still need our emotional (情感的) shelter till we finish our studies , and that is why we usually stay in our parents’ home until we feel grown up enough to deal with living alone .
【小题1】When does the relationship with parents start changing ?

Is human blood all the same? “Yes，” you may say．“It's all red．”

Well，it's not as simple as you might think．

Blood is made up of different parts，such as red blood cells，white blood cells，and platelets（血小板）．

Two chemical molecules（分子）on the red blood cells make people's blood different．Scientists mark one molecule "A" and the other molecule "B".

According to which and how many molecules are on the red cell, scientists divide blood into four types: A, B, AB and O.

Your blood type will stay the same your whole life.

Scientists have been wondering if there are some links between people's blood type and their personalities but they don't know for sure yet.

  But some say that people with the same blood type may have things in common.

What's your blood type? Do you have family members or friends who are the same type as you? Read the following. Are you like this?

People with type A: They look peaceful from the outside. But they ask too much of themselves that they may be very nervous inside. They get happy or sad easily. Sometimes they are shy but always very careful. They can easily win people's trust.

People with type B: They have strong minds. Once they start a task, they don't give up easily. They'll try their best to finish it and do it well. Type B people always try to make themselves different from others. They want to do things in their own way in life.

People with type AB: They are maybe the strangest among all blood types. They can be both open and shy, noisy and quiet at the same time! They are responsible （负责的） and always ready to help others.

People with type O: They're open and good at making friends. They always start tasks but don't always finish them. They have lots of new ideas and love to be the centre of attention. They always strongly believe in themselves.

1. What's the main subject of this passage?

A．blood types                                      B．blood types and personalities

C．personalities                                      D．scientific research on blood

2. The blood types are decided by ____________.

A．the amount of white blood cells

B．the amount of platelets

C．the kind and amount of molecules on the red cell

D．the kind and amount of molecules on the white cell

3. Scientists are ________ about the relation between blood types and personalities.

A．not sure                    B．quite sure            C．excited               D．worried

4. If a person always tries to be different from others, he/she might have _________ blood.

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

5. Which of the following is NOT true according to the passage?

A．A person's blood type will never change throughout his life.

B．A person's blood type might have something to do with his/her personality.

C．A person with type O blood is usually confident.

D．A person with type A blood has the strangest personality.