分别用“p或q”、“p且q”、“非p”填空:
①“菱形的对角线互相垂直平分”是____形式;
②“负数没有平方根”是____形式;
③“3≥3”是____形式;
④“△ABC是等腰直角三角形”是____形式
The teacher did what she could _____ that child.
20+50____70 20____70=90 10____30=40
80-30____50 20____20=0 60____20=40