按企业的内部结构分类，可以将企业分为（）、单厂企业和企业集团。
A.独资企业
B.联合企业
C.民营企业
D.企业集团
参考答案：B
The major goal of USB was to define an external expansion bus which makes adding (70) to a PC as easy as hooking up a telephone to a wall-jack. USB 2.0 is an evolution of the USB 1.1 (71) , providing a higher performance interface.
A．peripherals
B．outside
C．inside
D．beside
用数字万用表测量断路器分闸线圈电阻，欧姆档位应指向（）位置。
A.200
B.2K
C.200K
D.2M
