问题
填空题
根据下列句子及所给汉语注释，写出空缺处各单词的正确形式，每空只写一词。
1.How much did you ______ (花费) for the nice coat?
2.Music can make you ______(放松) after homework.
3. Lucy is too busy , let me go ________(代替).
4. He tried to stop smoking, and he ________(成功).
5. We had a __________(野餐) in the park last weekend.
答案
1.pay 2.relax 3.instead 4.succeed 5.picnic
，滑块A与斜面间的动摩擦因数为
，且
，滑块A、B叠放后轻放在斜面上，且始终保持相对静止，A上表面水平。则B受力的示意图为（ ）