阅读短文，从方框中选择适当的句子还原到短文中，使短文意思完整．

    Scientists think that many or most animals can't see colors．  1  ．To find out if dogs could see colors，scientists gave dogs food every time they played certain piece of music．  2  only when they heard this piece of music．They did not get ready to eat when they heard other pieces of music．

    Then the scientists gave the dogs food every time they showed them a certain color．The dogs got ready to eat when they saw thi s color．  3  ．Again the dogs got ready to eat．The colors were al l the same to them．  4  ，however．For example if  we put food in a red box and do this every day．A monkey wiIi always go to the red box to get the food．  5  if we then put food in a blue box．

1．____________  2．___________  3．___________4．_________  5．____________

Comets(彗星) are parts of our solar system. Like the planets, they go around the sun.
But comets are not made of solid rocks like planets. A comet is a ball of dust, stones, and ice. Many people call comets dirty snowballs.
The “snowball” may be only a few miles across. But when the sun heats the “snowball,” much of it is changed to gases. The gases spread out and form the comet’s head, which may be thousands of miles across.
A comet moves fast in its trip around the sun. But when we see it, the comet does not seem to move. That’s because it is so far away. The moon moves fast, but when you look at it, you can’t see any motion(运动). That’s because the moon is far away.
Each year astronomers(天文学家) discover new comets. Some of them are seen only once. They make one trip around the sun and then go away out into space. The sun’s gravity cannot hold them.
Other comets, like Halley, keep returning. They have been captured by the sun. Halley’s earliest visit was probably 3,000 years ago. It may keep returning for another 3,000 years.
But every time a comet goes around the sun, the comet loses part of itself. Gases and dust are pulled out of the comet. That’s why Halley is now dimmer（暗淡的） than it used to be. Next time it visits us, in 2062, it may be even dimmer. Each visit it may get dimmer and dimmer, until it finally disappears.
【小题1】What is this passage mostly about?

Mr Bean, who is silly, awkward (笨拙的)    1   always funny and enjoyable, is a world-famous comedy character on TV and in movies. He makes people    2 through a series of simple and funny acts   3  body languages. Rowan Atkinson is the   4  who plays Mr Bean. Mr Atkinson is quite   5   for playing Mr Bean. 
Rowan was born on January 6, 1955, and   6  his early years on the family farm with his mother, three older brothers and his strict father, who did not believe   7  the value of television. For a time, he attended the same school as Tony Blair, who was two years older than him. At the age of 13, he   8   at Newcastle University where he had the highest marks in his year. At Oxford he got his Master’s degree (硕士学位) in electrical engineering. He was particularly  9  fast cars, of which he has a large collection.
Rowan’s career change from an electrical engineer to a famous comedian was partly   10  some speaking problems he had in his childhood.
While he was still at primary school, Rowan had already shown great talent in    11  . Although his teachers predicted (预言) a career in acting, Rowan was not confident   12   he met a group of talented people at university, and he realized this could be a career for him. Another important event    13  . One day in 1976, he was playing around and making faces  14 . He realized something. “I discovered my face,” he said later. John Lloyd, who worked for the BBC, says, “When I watched Mr Atkinson act for the first time, I was   15  that he would be more famous than Chaplin.”

One night, I wondered what it would be like if I only asked questions. I decided that no matter what anyone said to me the next day, I would reply only with   36 .
I loved to read about scientists and their discoveries, and I knew that scientists always started their research with a question. I hoped that I could become a scientist. Maybe by asking questions, I could train my mind to be   37 .
I survived the morning easily. “Is there any egg?” I answered when my mother asked what I wanted for breakfast. “Is this seat taken?” I asked when my friend Mike asked where he was going to   38  on the bus.
In the classroom, Mr. Black spoke slowly and clearly while I listened carefully. The problem had been part of my homework the night before. I wrote the answer on the board, “Could the answer be 361?”
Mr. Black smiled and nodded. I thought,“How did I   39  to get through that?” I almost laughed because asking questions really was starting to become a   40 .
I thought I had made it safely through the whole day,   41  what I had come to consider my experiment blew up at the dinner table when my dad asked me about my day. “What do I always do?” I replied.
My parents looked at each other. My father   42  again. “Well, I hope you went to school,” he said.
“Uhhh … why would you think otherwise?” I asked. My parents exchanged another   43   
and were becoming annoyed.
“Do you think questions are a good way to train your mind to be active?” I asked.
“It   44  the question,” said my father. “Some questions are asked for   45  information. Those are good mind-training questions. Sometimes, people use questions to get the other person to say something. Sometimes people ask questions to get someone to agree with them. Those questions don’t really achieve anything.”
“I guess my experiment didn’t work,” I said, and I told my father about my   46 .
“I think it worked   47 !” my father said. “You made a discovery, didn’t you? What matters is that you have put your idea into practice.”