Ben goes to work ________ and his sister goes to work ________.
A:by car; on her bike
B:by a car; on her bike
C:by cars; by bikes
D:by his car; by bike
在程序语言中,下列符号分别表示什么运算*;\;∧;SQR;ABS?
①经济、科技和文化水平的不同 ② 地域的差异
③人口数量的不同 ④历史发展的差异