对一般负荷供电的中型变配电所当装有电磁操动机构时,合闸电源宜采用硅整流,分闸电源可采用()。
A.小容量镉镍电池
B.硅整流
C.110V蓄电池组
D.220V蓄电池组
参考答案:A
按要求写句子。
1. We go to school by bike. (对画线部分提问)
__________________________________________________________________________
2. Today is January 15th. (对画线部分提问)
3. Lucy has a new bike. (变为否定句)
4. I bought a gift for you in Beijing. (变为一般疑问句)
5. The children are flying kites. (变为否定句)
如图各种工具中属于省力杠杆的是:______,属于费力杠杆的是______(选填序号)