请找出下列图示中正确的实验操作( )
A:除去CO的CO2
B:萃取时振荡混合液
C:稀释浓硫酸
D:向试管中滴加液体
— Jim's mother dislikes cartoons in the Past, but now she likes to watch them with little Jim.
— Oh, just as the saying goes, .
Mary usually _______ up at five o’clock. ( )
Hainan is in the of China.
有一台内阻为1Ω发电机,供给一学校照明用,如图所示,升压比为1:4,降压比为4:1,输电线的总电阻R=4Ω,全校共22个班,每班有“220V,40W”灯6盏,若保证全部电灯正常发光,则: