I know he's been curious about everything, but that's . Be patient!
A:what do kids like
B:what kids like
C:what are kids like
D:what kids are like
光敏电阻R相当于控制电路中的____ (选填“开关”或“用电器”)。
X、Y、Z、M四种金属,已知X可以从Y的盐溶液中置换出Y:X和Z作原电池电极时,Z为正极;Y和Z的离子共存于电解液中,Y离子先放电;M的离子的氧化性强于Y的离子.则这四种金属的活动性由强到弱的顺序为( )