A:will not have received
B:needn’t have received
C:shouldn’t have received
D:couldn’t have received
已知M(1,-2),N(-3,-2),则直线MN与x轴,y轴的位置关系分别为( )
计算机执行下面的程序后,输出的结果分别是①____;②____.
关于下列区域自然特征的描述正确的是( )