伺服电机有（）两种类型。

A. 道德情感
B. 道德意志
C. 道德行为
D. 道德习惯

A. 频率变送器
B. 功率因数变送器
C. 电压变送器
D. 功率变送器

AS numbers are assigned by the IANA
B. AS numbers are used by BGP （Border Gateway protocol ） to exchange IP routing information with neighboring AS
C. In the internet， an Autonomous System （AS） is a collection of IP networks and routers under the control
D. All of the Above

A. 不能
B. 允许
C. 应为