A:killed
B:killing
C:to kill
D:having killed
0.52÷1.3=____
下列命题:
①三点确定一个圆;
②从圆外一点引圆的两条切线,它们的切线长相等;
③所有的正方形都有外接圆;
④三角形的外心到三角形各个顶点的距离相等;
正确的有( )
例:
—What are these?
—They are two cups.