题目

—What did Kate say just now?       —She asked _________. A. who has been to the USA in our class    B. what was wrong with my computer C. when did China become a member of the World Trade Organization D. that China had successfully held the Olympic Games   答案：B下列的几种现象中，内能转化为机械能的是A.冰块在地面上滑动时慢慢熔化B.菜刀在砂轮上磨，菜刀温度升高C.火柴摩擦后燃烧D.水沸腾时，推动煲盖振动