题目

Finally, the thief handed over everything ____ he had stolen to the police. A. that               B. which             C. whatever        D. all 答案：A学习了声音的产生和传播后，小明同学做了以下小结．请你在横线上为小明填上空缺．（1）悠扬的笛声是空气柱振动振动产生的．（2）笛声在15℃中的空气中的传播传播速度是340340m/s．