题目

如图所示，绳子OO′悬吊着质量忽略不计的杆，在杆的a点挂上重物G，在O右侧某点b处挂上钩码．重物G的质量及a到O的距离不变，要使杆保持水平，b点挂的钩码个数（各个钩码质量相同）和b到O的距离的关系是图7中哪一幅图: 答案：  B根据首字母或中文提示完成短文（每空一词）。One year ago, Kate was a【1】(害羞的)girl. Many things could affect her【2】(心情). She often felt unhappy. She wanted to m【3】friends with her classmates, but she didn’t know how to talk w【4】them. Jane was a nice girl, she often told Kate【5】(笑话)，asked Kate to do exercise with her, and【6】(发邮件) her to cheer her up. With the help of Jane , she doesn’t feel【7】(孤独的) any more and she becomes m【8】and more confident. Now she has enough【9】(勇气) to face everything. She believes nothing is【10】(不可能).