--- It rained cats and dogs this morning. I’m glad we took an umbrella.

--- Yeah, we would have got wet all over if we__________ .

A．hadn’t

B．haven't

C．didn't

D．don't

为核查仪器而选用在规定的示值或规定的被测值处的测量仪误差是（）

A.示值误差

B.基值误差

C.零值误差

D.固有误差