【多选题】直流电动机的调速方法以下说法正确的是
A.
调节电枢电压调速,属于无极平滑调速方法,调速范围宽
B.
电枢回路串电阻只能是有级调速,所串电阻上消耗电能,不经济
C.
弱磁升速,调速范围窄,一般与调压调速相配合使用
【单选题】调节远曲小管和集合管对水的重吸收的主要激素是
【单选题】串级控制系统中包含两个回路,主回路和副回路属于( )
【多选题】下列选项中,属于分程控制系统的应用范围的有( )。
【单选题】The United States is a country made up of many different races. Usually they are mixed together and cant be told from one another. But many of them still, talk about where their ancestors came from. I...
A.
reads at about 245 w. p. m.
C.
reads at about 300 w. p. m.
D.
cannot read difficult works in translation
【单选题】The white races are superior ______ the darker ones.
【判断题】侧滑测试时,车速应不大于5km/h。( )