阅读短文,并简要回答文后的问题。注意：答题时不得超过规定的字数。

When scientists look up into the night sky, they see stars, planets and the moon.  There is also dark matter the material between the stars and planets. Scientists believe dark matter makes up much of the matter in our universe.  However they have not been able to explain where it is.  Although scientists have discovered signs of its gravity, no one has been able to see dark matter until now.    

Recently scientists discovered observable dead stars -- or dark matter -- at the edge of our own Milky Way galaxy. The experts announced their discovery in Science Magazine.  They said they found thirty-eight objects called “white dwarfs.”  Each white dwarf is a burned up, dying star like the sun. However, each one has shrunk to about the size of Earth.  These newly discovered white dwarfs are said to be about four-hundred-fifty light years from Earth.  A light year is the distance that light travels in one year. 

Ben Oppenheimer led the research team that discovered the white dwarfs.  He works at the University of California at Berkeley.  He says the team studied pictures of the white dwarfs taken during the past thirty years.  The movement of the objects suggests that they are in the so-called “halo” of the universe. This is a very large circle of stars and gas that surrounds our Milky Way galaxy. 

This is important because the halo is much larger than the Milky Way galaxy itself.  The researchers suggest that there are many white dwarf stars throughout this halo.  This discovery would explain much of the mass that cannot be found in our galaxy.   

Mister Oppenheimer says most of the white dwarfs may be about ten-thousand-million years old. Scientists believe the universe was born about thirteen-thousand-million years ago after a huge explosion of matter called the Big Bang.  

Scientists estimate that most of the dark matter in our universe is made up of unusual particles(粒子). Scientists have not been able to identify these particles. Some scientists say the discovery opens the way for more study of the unexplained matter.

73. Find in the passage a word closest in meaning to the underlined word “halo”.

74. According to the scientists’ research, how far are the “white dwarfs”probably from us? （回答词数不超过8个）

75. What research will scientists most probably do about the dark matter?（回答词数不超过10个）

When the great library of Alexandria burned, the story goes, one book was saved. But it was not a valuable book; and so a poor man, who could read a little, bought it for a few coppers（铜钱）.The book wasn’t very interesting, but between its pages there was something very interesting indeed. It was a thin strip（条）of vellum（牛皮纸）on which was written the secret of the “Touchstone”!

The touchstone was a small pebble（小园石）that could turn any common metal into pure gold. The writing explained that it was lying among thousands and thousands of other pebbles that looked exactly like it. But the secret was this: The real stone would feel warm, while ordinary pebbles are cold.

So the man sold his few belongings, bought some simple supplies, camped on the seashore, and began testing pebbles. He knew that if he picked up ordinary pebbles and threw them down again because they were cold, he might pick up the same pebble hundreds of times. So, when he felt one that was cold, he threw it into the sea. He spent a whole day doing this but none of them was the touchstone. Yet he went on and on this way. Pick up a pebble. Cold-throw it into the sea. Pick up another. Throw it into the sea.

The days stretched into weeks and the weeks into months. One day, however, about mid-afternoon, he picked up a pebble and it was warm. He threw it into the sea before he realized what he had done. He had formed such a strong habit of throwing each pebble into the sea that when the one he wanted came along, he still threw it away.

So it is with opportunity. Unless we are vigilant（警惕的）, it’s easy to fail to recognize an opportunity when it is in hand and it’s just as easy to throw it away.

The book was special to the man because ______.

         A. it was made of vellum

         B. it was the only book that survived the great fire

         C. it was a story about how to tell the touchstone from ordinary stones

         D. it included the secret of the touchstone

He threw pebbles into the sea ______.

         A. to test how far he could throw

         B. to practice throwing pebbles

         C. to avoid picking up the same pebble once again

         D. to express his disappointment at failing to find the touchstone

What message does the story want to convey?

         A. Careful habits can lead to success.

         B. Habits can benefit you but also hold you back.

         C. Never judge a person or a thing by appearances.

         D. Opportunity only visits the ready and watchful mind

I start to wonder what else had changed since I’d been gone. My parents are in an awkward puzzle, wondering how to treat me now----whether to treat me—still their daughter—as one of them, an adult, or as the child they feel they sent away months earlier.
I run into two of my best friends from high school; we stare at each other, expressionless. We ask the simple questions and give simple answers. It’s as if we have nothing to say to each other. I wonder how things have changed so much in such a small amount of time. We used to laugh and promise that no matter how far away we were, our love for each other would never change. Their interests don’t interest me anymore, and I find myself unable to relate my life to theirs.
I had been so excited to come home, but now I just look at it all and wonder: Is it me? Why hadn’t the world stood still here while I was gone?  My room isn’t the same, my friends and I don’t share the same promise, and my parents don’t know how to treat me—or who I am, for that matter.
I get back to school feeling half-satisfied, but not disappointed. I sit up in my bed in my dorm room, surrounded by my pictures, dolls. As I wonder what has happened, I realize that I can’t expect the world to stand still and move forward at the same time.  I can change and expect that things at home will stay the same. I have to find comfort in what has changed and what is new; keep the memories, but live in the present.
A few weeks later, I’m packing again, this time for winter break. My mom meets me at the door. I have come home accepting the changes, not only in my surroundings, but most of all in me.
【小题1】
What can we infer about the writer?