焦炭抗碎强度用M10表示。
参考答案：错
They sat face to face, ________ about the things they were interested in for a long time.
A．and talk
B．talking
C．to talk
D．talked
把方程x2-8x-84=0化成（x+m）2=n的形式为（ ）
A．（x-4）2=100
B．（x-16）2=100
C．（x-4）2=84
D．（x-16）2=84
