题目内容
One afternoon in January 1989, Susan Sharp, 43, and her 8-year-old son, David, were walking hard【C1】______an icy parking lot,【C2】______Susan's cane slid on the ice. She【C3】______face first into the mud. David【C4】______to his mother's side.
"Are you all right, Mom？"
【C5】______, Susan pulled herself up. "I'm okay, honey, "she said.
It had been nearly two years since Susan had trouble walking. She was falling more【C6】______now. Every inch of ice was a【C7】______danger for her. "I wish I could do【C8】______," the boy thought. '
David, too, was having【C9】______of his own. The boy had a speech defect. At school he【C10】______asked questions or read aloud.
One day David's teacher announced a【C11】______assignment. "Each of you is going to come up with an invention," she said. This was for" INVENT AMERICA!", a national competition to encourage creativity in【C12】______
An idea hit David one evening.【C13】______only his mother's cane didn't slip on the ice, he thought. "That's it ! "David realized.
"What if I fixed your cane so a nail stretched out of the bottom？" he asked his mother.
"【C14】______the sharp end would scratch floors," Susan said.
"No, Mom. I could make it like a hall-point pen. You take your hand【C15】______the button and the nail returns back up. "Hours later the cane was finished. David and his father, Jeff,【C16】______as Susan used it to walk 50 feet across the【C17】______"It works!" she said.
In July 1989, David was declared national winner at the annual "INVENT AMERICA!" ceremony in Washington D. C.
As David began to make【C18】______appearances, he was forced to communicate more closely. Today, David is nearly【C19】______of his speech defect, and his cane is waiting to be widely used.【C20】______the boy who once people had trouble talking now hopes to start making canes for people who have trouble walking.
【C1】
查看答案
搜索结果不匹配？点我反馈
更多问题
听力原文：W: Hey, Margo! Do you know where the scissors are？
M: Aren't they in the desk drawer？
W: That's the first place I looked.
What can we infer from the conversation？
听力原文：W: You know those bananas in the cupboard？ Well , Willy's eaten the whole lot.
M: What？ Are you kidding？
W: No, I'm serious. And new she says she feels sick.
M: Well, it serves her fight for being so greedy.
What does the man mean？
What does the woman say has made her job easier？
The gravitational pull of the Earth and moon is important to us as we attempt to conquer more and more of outer-space. Here's why.
As a rocket leaves the Earth, the pull of the Earth on it becomes less and less as the rocket roars out into space. If you imagine a line between the Earth the pull of the Earth and the moon, there is a point somewhere along that line, nearer to the moon than to the Earth, at which the gravitation pull of both the Earth and the moon on an object is just about equal. An object placed on the moon side of that point would be drawn to the moon. An object placed on the Earth side of that point would be drawn to the Earth. Therefore, a rocket need be sent only to this "point of no return" in order to get it to the moon. The moon's gravity will pull it the rest of the way.
The return trip of the rocket to Earth is, in some ways, less of a problem. The Earth's gravitational field reaches far closer to the moon than does the moon's to Earth. Thus it will be necessary to fire an Earthbound rocket only a few thousand miles away from the moon to reach a point where the rocket will drift to earth under the Earth's gravitational pull.
The problem of rocket travel is not so much concerned with getting the rocket into space as it is with guiding the rocket after it leaves the Earth's surface. Remember that the moon is constantly circling the Earth. A rocket fired at the moon and continuing in the direction in which it was fired would miss the moon by a wide margin and perhaps continue to drift out into space until "captured" in another planet's gravitational field. To reach the moon, a rocket must be fired toward the point where the moon will be when the rocket has traveled the required distance. This requires precise calculations of the speed and direction of the rocket and of the speed and direction of the moon.
For a rocket to arrive at a point where the moon's gravity will pull it the rest of the way, it must reach a speed called velocity of escape. This speed is about 25,000 miles per hour. At a speed less than this, a rocket will merely circle the Earth in an orbit and eventually fall back to Earth.
This passage deals mainly with ______.
微信支付 
支付宝支付