消火栓灭火系统的室内消火栓给水管到若管径( )mm时，采用螺纹连接。
A．≤80B．≥80C．≤100D．≥100
参考答案：C
城市人口数量较大，城市的等级较高，城市的服务范围也较大。
When I was young, my father told me__________.
A．the earth went around the sun
B．did the earth go around the sun
C．the earth goes around the sun
D．does the earth go around the sun
