题干

全椒冬天的清晨,有时郊外草地上会出现一层白白的东西,太阳出来后一会就变成水了,最后不见了,它经历了怎样的物态变化(   )

A:液化﹣汽化﹣升华

B:凝华﹣熔化﹣汽化

C:汽化﹣升华﹣凝固

D:升华﹣熔化﹣凝华

上一题 下一题 0.0难度 选择题 更新时间:2019-07-05 01:44:17

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B

同类题2

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    The light from the campfire brightened the darkness, but it could not prevent the damp cold of Dennis's Swamp (沼泽地) creeping into their bones. It was a strange place. Martin and Tom wished that they had not accepted Jack's dare. They liked camping, but not near this swamp.

    “So,” Martin asked as they sat watching the hot coals. “How did this place get its name ? ”

    “Are you sure you want to hear it ? It's a scary story,” warned Jack.

    “Of course!” cried out Tom. “If there were anything to be scared of, you wouldn't have chosen this place!”

    “Ok, but don't say I didn't warn you,” said Jack, and he began this tale.

    “Way back in time, a man called Dennis tried to start a farm here. He built that cottage over there to live in . In those days, the area looked quite different — it was covered with tall trees and the swamp was a crystal-clear river. After three hard years, Dennis had cleared several fields and planted crops. He was so proud of his success that he refused to listen to advice.

    “ 'You are clearing too much land, ' warned one old man. ' The land is a living thing. It will hit back at you if you abuse it. '

    “ ' Silly fool,' said Dennis to himself. 'If I clear more land, I can grow more crops. I'll become wealthier. He's just jealous!'”

    “Dennis continued to chop down trees. Small animals that relied on them for food and shelter were destroyed. He was so eager to expand his farm that he did not notice the river flowing slowly towards his door. He did not notice salt seeping to the surface of the land. He did not notice swamp plants choking all the native plants.”

    “What happened? ” Martin asked. It was growing colder. He trembled, twisting his body closer to the fire.

    “The land hit back ---- just as the old man warned, ” Jack shrugged. “Dennis disappeared Old folks around here believe that swamp plants moved up from the river and dragged him underwater. His body was never found.”

    “What a stupid story, ” laughed Tom. “Plants can't …” Before he had finished speaking, he screamed and fainted (晕倒). The other two boys jumped up with fright, staring at Tom. Suddenly, they burst out laughing. Some green swamp ivy (常春藤) had covered Tom's face. It was a while before Tom could appreciate the joke.

同类题3

完形填空

    His palms were sweating. He needed a towel to dry his grasp. The sun was as hot as the 1 he faced today at the National Junior Olympics. The bar (横竿) was set at 17 feet. That was three inches higher than his personal best. Michael Stone faced the most 2 day of his pole-vaulting(撑竿跳高) career.

    You couldn't tell whether Michael Stone was surprised, excited or vain about clearing the bar at 17 feet. As soon as he 3 on the inflated(充了气的) landing mat, Michael immediately began 4 for his next attempt at flight. He seemed 5 the fact that he had just beaten his personal best 6 three inches and that he was one of the first two competitors in the pole-vaulting 7 at the National Junior Olympics.

    When Michael 8 the bar at 17 feet 2 inches and 17 feet 4 inches, again he showed no 9. As he lay on his back and 10 the crowd sigh, he knew the other vaulter had missed his final jump. He knew it was time for his final jump. Since the other vaulter had 11 misses, Michael needed to clear this vault to win. A 12 would get him second place. It was nothing to be ashamed of,13 Michael would not 14 himself to have the thought of not winning first place.

    He rolled over and found his pole, stood and stepped on the runway that 15 the most challenging event of his 17-year-old life.

    As he sprinted (冲刺) down the runway, something felt wonderfully different, yet familiar. When he took a deep breath, it happened. He began to 16 like an eagle.

    He later went on that day to clear 17 feet 6 inches: a new National and International Junior Olympics record.

    With all the media attention and sponsorship possibilities, Michael's life would never be 17 again. It wasn't just because he won the National Junior Olympics and18 a new world record. And it wasn't because he had just increased his personal best by 9 inches. It was simply because Michael Stone is blind.

    A chance encounter can sometimes make all the 19 to whether hardship brings 20 the best in us or the worst.