D
It could become possible for humans to live for up to 800 years. This is what researchers are saying at the University of California. They have made a scientific discovery using ordinary yeast（酵母菌）；the kind you find in bread.
The scientists were looking at live yeast and removed（移动）two genes（基因）. These two genes can help make the yeast grow old. They are the same genes that also cause cancer（癌症）in humans. The scientists then put the yeast without two genes on a diet! This made the yeast live ten times longer than normal.
Valter Longo, the head scientist of the project，says that although human and yeast genes are different, the way to make things live longer is the same. If scientists improve this way, humans could live much longer too.
Longo also thinks that there is another gene that is helpful for making use age. If we can also find this gene and removed it, then it might be possible to live to an amazing age.
Other scientists don’t think this is possible. They think that humans can’t live for more than 125 years. The oldest known person in the world, Jeanne Calment, died at the age of 122 years and 164 days. Most scientists think that she was one of the few lucky ones to almost reach the maximum human age limit（极限）.
However, it is true that more humans are living longer than ever before. In Britain, there is a huge number of people living past 100. Nearly 9000 people are 100 or older now, compared to only 100 people in 1911. There are still far more woman than men in this age group — seven women for every man. So, if you want to live a long time, the best thing to be is female!
27.What does the underlined “This” refer to ?
A. Scientists looked at live yeast to make better food.
B. Scientists put the yeast without two genes on a diet.
C. Scientists found the same genes in humans and the yeast.
D. Scientists removed two certain genes from human bodies.
28. According to the passage, what did researchers find?
A. Yeast without two genes lives longer than normal.
B. All the genes in live yeast and humans are the same.
C. Humans can live for up to 800 years old in Britain.
D. More humans are living shorter lives than before.
29.Why do some scientists take Jeanne Calment as an example?
A. To show people that she was the oldest person in the world.
B. To tell people how lucky she was to reach human age limit.
C. To explain why they think people can’t live to an amazing age.
D. To ask people to find out how they can live as long as she does.
30.Where can you probably see this article?
A. In a science magazine.
B. In a food recipe.
C. In a geography book.
D. In a history note.
BACA
It could become possible for humans to live for up to 800 years. This is what researchers are saying at the University of California. They have made a scientific discovery using ordinary yeast（酵母菌）；the kind you find in bread.
The scientists were looking at live yeast and removed（移动）two genes（基因）. These two genes can help make the yeast grow old. They are the same genes that also cause cancer（癌症）in humans. The scientists then put the yeast without two genes on a diet! This made the yeast live ten times longer than normal.
Valter Longo, the head scientist of the project，says that although human and yeast genes are different, the way to make things live longer is the same. If scientists improve this way, humans could live much longer too.
Longo also thinks that there is another gene that is helpful for making use age. If we can also find this gene and removed it, then it might be possible to live to an amazing age.
Other scientists don’t think this is possible. They think that humans can’t live for more than 125 years. The oldest known person in the world, Jeanne Calment, died at the age of 122 years and 164 days. Most scientists think that she was one of the few lucky ones to almost reach the maximum human age limit（极限）.
However, it is true that more humans are living longer than ever before. In Britain, there is a huge number of people living past 100. Nearly 9000 people are 100 or older now, compared to only 100 people in 1911. There are still far more woman than men in this age group — seven women for every man. So, if you want to live a long time, the best thing to be is female!
27.What does the underlined “This” refer to ?
A. Scientists looked at live yeast to make better food.
B. Scientists put the yeast without two genes on a diet.
C. Scientists found the same genes in humans and the yeast.
D. Scientists removed two certain genes from human bodies.
28. According to the passage, what did researchers find?
A. Yeast without two genes lives longer than normal.
B. All the genes in live yeast and humans are the same.
C. Humans can live for up to 800 years old in Britain.
D. More humans are living shorter lives than before.
29.Why do some scientists take Jeanne Calment as an example?
A. To show people that she was the oldest person in the world.
B. To tell people how lucky she was to reach human age limit.
C. To explain why they think people can’t live to an amazing age.
D. To ask people to find out how they can live as long as she does.
30.Where can you probably see this article?
A. In a science magazine.
B. In a food recipe.
C. In a geography book.
D. In a history note.
BACA
