A:①②
B:②③
C:③④
D:①④
We teenagers should the old and offer our seats to them on buses.
P1(x1,y1),P2(x2,y2)是正比例函数y=﹣x图象上的两点,则下列判断正确的是( )
已知复数z满足(3+i)z=10i(其中i是虚数单位,满足i2=﹣1),则复数z的共轭复数是( )