工件以精基准孔定位时，不采用（）作定位元件。
A.圆柱心轴
B.定位销
C.小锥度心轴
D.轴套DZ
参考答案：D
下列物质对应的化学式不正确的是[ ]
A．氧化镁--MgO
B．水--H2O
C．氧气--O
D．氧化铜--CuO
The one million people of the city,________ thought little of these events , _______to bed as usual that night .
A．which…going
B．where…went
C．who…went
D．who… going
