题目

如果mn<0，且m>0，那么点P(m2，m-n)在（    ） A．第一象限    B．第二象限    C．第三象限    D．第四象限 答案：A If we travel a short distance, we should walk _____ taking a bus. Then we’ll be greener people. A.instead of                  B.because of                    C.short of