电磁波传播的速度是（）。

A.3×10⁹m／s

B.3×10⁸m／s

C.3×10⁷m／s

D.3×10⁶m／s

E.3×10⁵m／s

Although it was obvious that his friend had cheated him, he      her. He was a bit out of control himself.

A．shouldn’t hit

B．shouldn’t have hit

C．mustn’t hit

D．mustn’t have hit