题目

如图所示实验或事例，属于内能转化为机械能的是A. 由滑梯滑下臀部会有灼热感B. 搓手取暖C. 钻木取火D. 水蒸气将木塞冲出 答案：【答案】D【解析】A．由滑梯滑下臀部会有灼热感，是摩擦做功，机械能转化为内能，不合题意；B．搓手取暖是摩擦做功，机械能转化为内能，不合题意。C．钻木取火是摩擦做功，机械能转化为内能，不合题意；D．水蒸气将木塞冲出，是气体对外做功，将内能转化为机械能，符合题意；25、Mrs Brown had a small garden behind her house, and in spring she planted some vegetables in it. She looked after them very carefully, and when summer came, they looked very nice. One evening Mrs Brown looked at her vegetables and said, “Tomorrow I am going to pick them, and then we can eat them.” But early the next morning, her son ran into the kitchen and shouted, “Mother! Come quickly! Come quickly! Our neighbour’s ducks are in the garden and they are eating our vegetables!” Mrs Brown ran out, but it was too late! All the vegetables were eaten up! Mrs Brown cried, and her neighbour was very sorry, but that was the end of the vegetables. Then a few days before Mrs Brown birthday, the neighbour brought Mrs Brown a bag. In it was a beautiful, fat duck, and on it was a piece of paper with the words, “Enjoy your vegetables!” 1. Mrs Brown planted some ______ in her garden. A. vegetables       B. apples      C. potatoes          D. flowers 2. Mrs Brown was going to pick the vegetables, so that they could ____ them. A. sell                B. use         C. eat          D. clean 3.____ found that the ducks were eating the vegetables in the garden. A. Mrs Brown         B. Mrs Brown’s daughter  C. Mrs Brown’s son    D. Mr Brown 4. When the ducks ate up the vegetables, the neighbour ____. A. cried              B. was very happy    C. laughed                   D. was very sorry 5. The neighbour sent Mrs Brown ____ as a birthday present. A. a big cake    B. a fat duck                C. some vegetables   D. a garden 评卷人 得分 四、阅读填空 （每空？ 分，共？ 分）