A. restaurant B. company C. library D. driver E. policeman F. policewoman
⑴ ____ ⑵ ____
⑶ ____ ⑷ ____
⑸ ____ ⑹ ____
①甲图中,____应改为____。
②乙图中,____应改为____。
We should wear special boots __________ us floating away into the space .
将分别标有“6V,6W”和“6V,3W”的两只灯泡串联到电源的两端,电源内阻为2Ω,要使两个灯泡都不被烧坏,电源的电动势最大为( )