Sleep puzzles（使……困惑）science all the time. ___3___and doctors would like to talk about why one can't fall asleep. They are not so sure ___4___ causes sleep.

　　Strange things ___7___ during sleep. For example, you often move during your sleep. You would feel ___8___ if you didn't move. You also ___9___ Part of your brain（大脑）is still ___10___ when you dream.

　　It was early morning. Peter Corbett helped Mark Wellman out of his wheelchair and onto the ground. They stood before El Captain, a huge rock almost 1.2 kilometers high. Mark had long dreamed to climb El Captain when he was a child. At the age of twenty—one, he had fallen while climbing a mountain, losing his legs. But he never lost his love for life.

　　Mark knew he couldn’t finish the climb alone, but his friend Peter would be there to lend a helping hand. They thought it would take them seven days to reach the top. Now Peter climbed about 30 meters up and hit a piton(岩钉）into the rock. Tying one end of a 50—meter rope to the piton, he let the other end of the rope fall down. Mark caught the rope and tied it to his belt(腰带). He next readied above his bead and tied a T—bar(丁字铁）to the rope. Mark took a deep breath, pushed the T-bar up almost as far as his arms could reach, and began the first pull-up. High above，Peter let out a cheer, “You’re on your way.”

　　For the first four days the two men progressed upward without accident. But on the fifth day，a very strong wind began to blow, making it hard for Mark to hold on to his rope. But Mark kept on pushing up the T-bar and pulling himself up.

　　It took them one more day than they had expected. But as the two heads appeared, the group of people waiting on the top went wild with joy.

　　根据材料内容选择最佳答案。

46.The underlined word “readied” in the second paragraph means______.

       A.抵达      B.够到    C.完成    D.伸出

47.While climbing, Mark       _____.

　　       A.carried the T-bar on his back and stepped upward

　　   B.pushed up the T-bar and pulled himself up

　　   C.sat in his wheelchair and pushed himself up

　　   D.held on to the rope drawn up by his friend

48.The correct order of the steps before Mark’s climbing is______.

　　　a. push up the T-bar   b. tie the rope to his belt

　　　c. hit the piton into the rock      d. tie the T-bar to the rope

　　　e. tie the rope to the piton

  A. c-e-b-d-a       B. e-c-a-b-d C. e-b-d-c-a D. b-d-e-c-a

49.Which of the following is TRUE of Mark Wellman?

　　A.He realized his dream without anyone helping him.

　　B.He was badly injured when he climbed El Captain.

　　C.He climbed up the rock about 170 meters in height each day.

　　D.He had dreamed to climb up El Captain for a long time.

50.This passage mainly shows us that______.

　　A.a good beginning is half done     B. it is never too old to learn

　　C.doing is better than saying  D. where there is a will, there is a way