备用电源自动投入装置启动部分的作用是当母线因各种原因失去电压时,断开_________电源,而自动合闸部分的作用则是将_________电源投入。
参考答案:工作,备用
Have you seen Mary lately? My boss wants to know__________.
A.how she is getting along
B.how is she getting along
C.what she is getting along
D.what is she getting along
身体运动的构成要素有哪些?