Back in old times, people had little knowledge about the universe and nature. Things we now consider to be common sense were mysteries to our ancestors.

Over the years, major breakthroughs have been made in science and many phenomena have been explained. But still, there are always questions we can't yet answer, and The Guardian has listed some of them.

1. What makes us human?

Just looking at your DNA won't tell you - human DNA is 99 percent identical to that of the chimpanzee and, believe it or not, 50 percent identical to a banana's! A lot of the things we once thought were unique about us - language and tool use, recognizing ourselves in the mirror and so on – have since been seen in other animals. Perhaps it's our culture that makes the difference or maybe our ability to use fire. It's also possible that our capacity (能力) for co-operation and our trading skills are what make us unique.

2. Why do we dream?

Given the fact that we spend around a third of our lives sleeping, shouldn't we know everything about it? Unfortunately, scientists are still searching for a complete explanation of what happens when we sleep and why we dream.

Austrian psychologist Sigmund Freud believed dreams were the expressions of wishes that we can't fulfill in our real lives. Others have wondered whether dreams are just random "noise" coming from a sleeping brain.

3. Could we someday live forever?

Apart from accidents, most people die because of diseases that can be treated and aging. And since many diseases, such as diabetes（糖尿病） and cancer, are diseases of aging, treating aging itself could be the key to extending our lives.

Our knowledge of what causes us to age - and what allows some animals to live longer than others - is expanding rapidly. And though we haven't quite worked out all the details, we've worked out some pieces of the puzzles such as DNA damage and metabolism (新陈代谢), which are all leading to the invention of drugs that can slow down the aging process.

If we're lucky enough to lengthen our lives, we might even get to see the day when all of these questions are answered.

1.The main point of the passage is ______.

A. to inform people of the knowledge about the universe and nature

B. to introduce major breakthroughs that have been made in science

C. to present some questions we can't yet answer

D. to explain what were once mysteries to our ancestors

2.Chimpanzees and bananas are mentioned as examples to prove that ______.

A. human beings are actually not different from other animals

B. animals have completely different DNA from that of plants

C. both animals and plants share the same amount of DNA

D. DNA alone is not good enough to make humans different

3.The underlined word "identical" is closest in meaning to ______.

A. mysterious          B. unique     C. advanced             D. same

4.Which of the following statements is TRUE according to the passage?

A. What were mysteries to our ancestors are considered to be common sense now.

B. Now we know much more about dreams than our ancestors did in the past.

C. With the invention of new drugs people can possibly live even longer.

D. If all the diseases can be treated people can theoretically live forever.

Just as the teacher hands out the spelling test, you see Jeff pull out a small piece of paper with a lot of small words on it. Jeff hides the note into his hand but soon takes it out again. While he's taking the test, you see him looking back and forth between the teacher and his paper. There's no mistaking it — he's cheating.

Cheating can happen in a lot of different ways. When people cheat, it’s not fair to other people, like the kids who studied for the test or who were the true winners of a game.

Many people like the action of cheating. It makes difficult things seem easy, like getting all the right answers on the test. But it doesn’t solve the problem of not knowing the material and it won’t help on the next test—unless the person cheats again.

Some people lose respect for cheaters and think less of them. The cheaters themselves may feel bad because they know they are not really earning that good grade. And, if they get caught cheating, they will be in trouble at school, and maybe at home, too.

Some kids cheat because they’re busy or lazy and they want to get good grades without spending the time studying. Other kids might feel like they can’t pass the test without cheating. Even when there seems to be a “good reason” for cheating, cheating isn’t a good idea.

If you were sick or upset about something the night before and couldn’t study, it would be better to talk with the teacher about this. And if you don’t have enough time to study for a test because of swim practice, you need to talk with your parents about how to balance swimming and school.

A kid who thinks cheating is the only way to pass a test needs to talk with the teacher and his or her parents so they can find some solutions together. Talking about these problems and working them out will feel better than cheating.

1.The author thinks that when kids cheat in class, _______.

A．it is unfair to other people

B．it does harm to their heath

C．teachers should punish them

D．teachers shouldn’t stop them at once

2.Some students like cheating mainly because _______.

A．the material in the test is very difficult

B．they want to do better than the others

C．cheating can make hard things seem very easy

D．they have little time to study

3.The fifth paragraph mainly tells us ______.

A．cheating isn’t a good idea

B．why kids cheat in the test

C．some kids can’t pass the test without cheating

D．some kids don’t spend time studying

4.We can learn from the passage______.

A．cheaters are often thought highly of

B．people show no respect for those who cheat

C．parents whose kids cheat are often in trouble

D．kids cheat in the test because of swim practice

5.Those who cheat are advised to ______.

A．spend more time on school than on sports

B．find good solutions instead of cheating

C．try hard to be intelligent rather than lazy

D．ask their classmates for good methods of study

Many people often lose their friends and they don’t know how to keep a long friendship.So how can you keep a long friendship? The following passage explains very well about this matter.

The first thing you need to do is to become a good listener.In this way，you show your friends that you are interested in their lives.You want to know more about them and you want to help them solve their problems.They will cherish the friendship more if they know you care about them.

The next thing is that you should respect other people’s privacy (隐私)．People usually don’t like others to know about their private life，so you should show respect toward their privacy.Sometimes，they need some suggestions from others，but this does not mean that others can know about their entire life.So respect for privacy is a must for keeping a long friendship.

The third important thing is that you need to be able to forgive.You must remember that nobody is perfect in this world.It is important to forgive others and not to blame them for the mistakes they have already made.You are not perfect either.Thus you need to apologize to others for the mistakes you may have made.

Pay attention to the three things above，and you will be able to have long friendships.

46．This passage is written to tell us________.

A．why a long friendship is important

B．what we can do for our friends

C．how to make friends with others

D．how to keep a long friendship

47．According to the passage，what is the first thing that we need to do?

A．To know more about our friends.

B．To share our happiness and sadness.

C．To be good at listening to our friends.

D．To help our friends solve their problems.

48．What does the writer suggest you do if your friend makes a mistake?

A．Blame him.                                    B．Forgive him.

C．Tell him why it is so.                      D．Leave him immediately.

49．The writer most probably thinks that________.

A．everyone makes mistakes

B．some people are perfect

C．people often make stupid mistakes

D．we shouldn’t apologize fpr every mistake