题目

计算a4•a的结果等于_______． 答案：【答案】a5【解析】根据同底数幂相乘，底数不变指数相加计算即可求解.解：a4•a=a4+1= a5.故答案为：a5. The traffic rule says young children under the age of four and ____ less than 40 pounds must be in a child safety seat.    A. being weighed     B. to weigh     C. weighed          D. weighing