因接线盒受潮造成数字跳变，解决方法为（）。

A.配备稳压电源

B.晾晒或电吹风吹干

C.更换传感器

--Mike, can you tell us something about our new teacher?

-- Oh, sorry. I know nothing because I _____________ him before.

A．saw

B．didn’t see

C．have seen

D．haven’t seen