A:左眼观察,右眼睁开
B:右眼观察,左眼睁开
C:左眼观察,右眼闭合
D:右眼观察,左眼闭合
— I can’t do it______ anymore. I need help.
—What’s wrong with the baby, doctor?
—_______. Just a slight cold.
已知△ABC三顶点坐标A(1,2),B(3,6),C(5,2),M为AB中点,N为AC中点,则中位线MN所在直线方程为( )