Have you ever wondered why stems(茎)grow upwards and roots downwards? Why do plants always seem to turn towards the light and climbing plants run up rather than down? The answer is simple: auxin(生长素), a chemical substance that controls growth in plants.

    Auxin gives away its secrets

Auxin is a plant hormone(激素). Darwin was already interested in it in the 19th century. Only in recent years, however, has the hormone started to give away its secrets, thanks to intensive molecular research. Auxin is produced in the young, growing parts of plants and then transported throughout the plant—to a low­lying stem for example. The stem needs to straighten out as soon as possible to be able to absorb the topside, resulting in the underside growing faster and the stem straightening out. For the same reason, plants in front of windows will always turn to the light. This active regulation of auxin transport allows plants to take ideal advantage of local and changing conditions.

   A new means of transport for auxin

   The transport of auxin through the plant plays a vital role. And, from all appearances, it is not a simple matter. The researchers identified an important new link and means of transport for auxin: PILS proteins (蛋白质). PILS proteins are vital for auxin­dependent plant growth and adjust the intracellular(细胞内的)storage of the hormone. It is exactly this compartmentalizing (分类) of auxin that seems functionally important for the various developmental processes.

Growing crops more efficiently: the right amount of auxin in the right place

 Higher auxin levels at the right moment and in the right place result in better growth and greater harvest. Better adjustment of auxin levels would make plants grow more efficiently. The researchers hope to contribute to the development of more efficient growing processes by continuing to sort out auxin transport processes.

 66. Which of the following is TRUE of auxin according to the text?

A. It helps the plant to bend at the right places while growing.

B．It prevents the roots of plants from growing faster.

C．It is no use when the surroundings have changed.

D．It helps the underside of plants grow faster than the topside.

67. What would make plants grow more efficiently?

A. Straightening out the stem.

B．The right amount of auxin in the right place.

C．Allowing plants to turn to the light.

D．Enough PILS proteins.

68. From Paragraph 3 we know that ________.

A. the researchers are not so sure if the transport for auxin is a new one

B．the levels of auxin remain the same during the growing processes of plants

C．PILS proteins delay the growth of plants

D．PILS proteins play an important part in the transport of auxin

69．According to Paragraph 2, the researchers got their results mainly by ________.

A. referring to Darwin's theory

B．observing plants straightening

C．doing intensive molecular research

D．watching plants in different places

70．Which of the following can be the best title for this passage?

A. Why Plants Grow Towards the Light?

B．Darwin's Dream Has Come True

C．How Did Scientists Find Out the Secret?

D．A New Way of the Growing of Plants

Lucky is the man who has no “skeleton in his closet.” When a man has done something in his life that he is ashamed of, that he wants to hide, he is said to have a “skeleton in his closet.” Some people may have more than one skeleton.
As we have noted many times, it is hard to find out how these expressions begin. Sometimes, we get some hard facts. But more often we have to depend on guesswork. And that is true of this phrase, which came from England.
Before 1832, English law did not permit a doctor to cut open a dead human body for scientific examination, unless it was the corpse(尸体) of an executed(处决) criminal.
But when it became legal, more and more doctors demanded skeletons for a more scientific study of medicine. It was helping in the advance of modern medicine. The demand had become so strong that men began to rob tombs and sell skeletons to doctors at high prices.
We are told that a doctor would usually buy just one skeleton for scientific study. It became very important in his work. But he had to keep it hidden because most people objected to keeping such a thing. As a rule, the doctor keep his skeleton in some dark corner where it could not be seen, or hide it in a closet.
After a time, people began to suspect every doctor of hiding a skeleton in the closet. From this suspicion, the phrase“a skeleton in the closet”took on a broader, more general meaning: to describe anything that a man wanted to keep others from discovering. It could be proof of a criminal act, or something much less serious. Well, that is one theory.
One writer, however, believes that the phrase might have come from something that really happened. It is his guess that a hidden closet in some old English country home may have turned up a real skeleton, clear proof of some old family shame or crime. Well, one man's guess is as good as another. But this sounds like a story by the great French novelist, Balzac.
Balzac tells us of a man who suspected his wife of having a lover. The husband comes home by surprise. But she hears him and quickly hides her lover in the closet of her bedroom. He enters her room and asks her if she is hiding her lover. He says he will not open the door to the closet if she promises him there is no one there; He will believe her. She answers firmly that she is not hiding anyone in the closet.
The husband then begins to build a solid brick wall against the closet. His wife watches, knowing that her lover will never come out alive. But she will not change her story and admit her guilt

1. 1.

   Which of the following situations is now suitable for using the phrase “skeleton in the closet”?

   1. A.
      You have stolen something precious and hide them in the closet
   2. B.
      You are a doctor and have to keep a skeleton for research
   3. C.
      If you have cut open a dead human body for scientific examination you should keep the
      skeleton secret
   4. D.
      You have done a crime or done something foolish, but you want to keep others from discovering it
2. 2.

   Which of the following is right according to the text?

   1. A.
      In the 19th century, doctors realized the importance of anatomy (解剖) in the development of
      medicine
   2. B.
      The doctors of the ancient times liked to collect as many skeletons as possible
   3. C.
      The thieves stole skeletons from tombs in order to help the doctors
   4. D.
      It is legal that corpses of anybody are cut open for scientific examination in history
3. 3.

   From the story Balzac told we know that the wife's lover must have become ______

   1. A.
      a corpse
   2. B.
      a phrase
   3. C.
      a skeleton
   4. D.
      a story

Lucky is the man who has no “skeleton in his closet.” When a man has done something in his life that he is ashamed of, that he wants to hide, he is said to have a “skeleton in his closet.” Some people may have more than one skeleton.
As we have noted many times, it is hard to find out how these expressions begin. Sometimes, we get some hard facts. But more often we have to depend on guesswork. And that is true of this phrase, which came from England.
Before 1832, English law did not permit a doctor to cut open a dead human body for scientific examination, unless it was the corpse(尸体) of an executed(处决) criminal.
But when it became legal, more and more doctors demanded skeletons for a more scientific study of medicine. It was helping in the advance of modern medicine. The demand had become so strong that men began to rob tombs and sell skeletons to doctors at high prices.
We are told that a doctor would usually buy just one skeleton for scientific study. It became very important in his work. But he had to keep it hidden because most people objected to keeping such a thing. As a rule, the doctor keep his skeleton in some dark corner where it could not be seen, or hide it in a closet.
After a time, people began to suspect every doctor of hiding a skeleton in the closet. From this suspicion, the phrase“a skeleton in the closet”took on a broader, more general meaning: to describe anything that a man wanted to keep others from discovering. It could be proof of a criminal act, or something much less serious. Well, that is one theory.
One writer, however, believes that the phrase might have come from something that really happened. It is his guess that a hidden closet in some old English country home may have turned up a real skeleton, clear proof of some old family shame or crime. Well, one man's guess is as good as another. But this sounds like a story by the great French novelist, Balzac.
Balzac tells us of a man who suspected his wife of having a lover. The husband comes home by surprise. But she hears him and quickly hides her lover in the closet of her bedroom. He enters her room and asks her if she is hiding her lover. He says he will not open the door to the closet if she promises him there is no one there; He will believe her. She answers firmly that she is not hiding anyone in the closet.
The husband then begins to build a solid brick wall against the closet. His wife watches, knowing that her lover will never come out alive. But she will not change her story and admit her guilt.
【小题1】Which of the following situations is now suitable for using the phrase “skeleton in the closet”?

Lucky is the man who has no “skeleton in his closet.” When a man has done something in his life that he is ashamed of, that he wants to hide, he is said to have a “skeleton in his closet.” Some people may have more than one skeleton.

As we have noted many times, it is hard to find out how these expressions begin. Sometimes, we get some hard facts. But more often we have to depend on guesswork. And that is true of this phrase, which came from England.

Before 1832,English law did not permit a doctor to cut open a dead human body for scientific examination, unless it was the corpse（尸体） of an executed（处决） criminal.

But when it became legal, more and more doctors demanded skeletons for a more scientific study of medicine. It was helping in the advance of modern medicine. The demand had become so strong that men began to rob tombs and sell skeletons to doctors at high prices.

We are told that a doctor would usually buy just one skeleton for scientific study. It became very important in his work. But he had to keep it hidden because most people objected to keeping such a thing. As a rule, the doctor kept his skeleton in some dark corner where it could not be seen, or hide it in a closet.

After a time, people began to suspect（怀疑） every doctor of hiding a skeleton in the closet. From this suspicion, the phrase“ a skeleton in the closet” took on a broader, more general meaning. To describe anything that a man wanted to keep others from discovering. It could be proof of a criminal act, or something much less serious. Well, that is one theory.

One writer, however, believes that the phrase might have come from something that really happened. It is his guess that a hidden closet in some old English country home may have turned up a real skeleton, clear proof of some old family shame or crime. Well, one man's guess is as good as another. But this sounds like a story by the great French novelist, Balzac.

Balzac tells us of a man who suspected his wife of having a lover. The husband comes home by surprise. But she hears him and quickly hides her lover in the closet of her bedroom. He enters her room and asks her if she is hiding her lover. He says he will not open the door to the closet if she promises him there is no one there; He will believe her. She answers firmly that she is not hiding anyone in the closet. The husband then begins to build a solid brick wall against the closet. His wife watches, knowing that her lover will never come out alive. But she will not change her story and admit her guilt.

1. Which of the following situations is suitable for using the phrase “skeleton in the closet”?

A．You have stolen something precious and don't want it discovered.

B．You are a doctor and have to keep a skeleton for research.

C．If you have cut open a dead human body for scientific examination you should keep the skeleton secret.

D．You have done a crime or done something foolish, but you want to keep others from discovering it.

2. From the text we know that there are ______ theories about how the phrase “skeleton in the closet” came into being.

A．one               B．two              C．three            D．four

3. Which of the following is right according to the text?

A．In the 19th century, doctors realized the importance of anatomy（解剖） in the development of medicine.

B．The doctors of the ancient times liked to collect as many skeletons as possible

C．The thieves stole skeletons from tombs in order to help the doctors.

D．It is legal that corpses of anybody are cut open for scientific examination in history.

4. From the story Balzac told we know that the wife's lover must have become ______.

A．a corpse           B．a phrase            C．a skeleton        D．a secret