题目

计算：＝（ ）A. 3 B. ﹣3 C. ±3 D. 9 答案：【答案】A【解析】表示9的算术平方根，根据算术平方根的定义即可求解．解：∵32＝9∴＝3故选：A．29、John was very upset because he has been charged by the police     breaking the law. A．about          B．in          C．for          D．with