---- What do you know about the population of China?

---- It _____ over 1,200 million and 80 percent of it _____ peasants.

A．is; is

B．are; are

C．are; is

D．is; are

用绝缘棒拉合隔离开关或经传动机构拉合隔离开关和断路器时，应注意什么？