题目

His father makes a living           driving a taxi. A  by              B  with                   C for                   D  through 答案：A下列运算中，错误的是（ ）A．2a﹣3a=﹣a B．（﹣ab）3=﹣a3b3 C．a6÷a2=a4 D．aa2=a2