— Millie, ________ late for school again.
— Sorry, I won't.
A:isn't
B:doesn't be
C:don't be
D:won't be
①中国恢复联合国席位
②尼克松总统访华
③中美两国正式建交
④邓小平访问美国
We ________ girls, but we look strong.
函数y=x2+bx+c与y=x的图像如图所示,有以下结论:
①b2﹣4c>0;②3b+c+6=0;③当1<x<3时,x2+(b﹣1)x+c<0;
④ b2+c2=32 ,其中正确的有____