【判断题】改变旋转磁场的转向即可改变电动机的转向,即:任意交换接入定子绕组三相电源中的两相,电动机就会反转。
【单选题】I insisted he______ back the wallet to the lady, but he insisted he______it.
【判断题】三相电动机的正反转控制中,改变电动机三相交流电源中任意两相的相序,即可改变电动机的旋转方向。
【单选题】His father insisted on punishing him, but he insisted he had _______ to do with the matter.
【单选题】His father insisted _____ him, but he insisted he _____ nothing to do with the matter. [ ]
A.
on punishing; should have
D.
he punish; should have
【单选题】He insisted that his bike ______ stolen and his wife insisted he ______ have to telephone the police. [ ]
【简答题】区分下列每组词的含义有何不同 ( 1 )脂和酯 ( 2 )脂类和类脂 ( 3 )磷酸酯和磷脂酸 ( 4 )混合甘油酯和甘油酯混合物
【判断题】在雾视时,应该让被检者平视看远,以减少调节因素造成的误差。
【单选题】Tom insisted that what he said _____ true, and insisted that he _____ punished.
【单选题】为了实现三相异步电动机的正反转功能,只要将三相电源中的( ),改变旋转磁场的方向,即可改变电动机的转向。