A:to clean, to do
B:cleaning, doing
C:cleaning, to do
D:to be cleaned, doing
2013的相反数是( )
如图所示,电源电压为3V保持不变,两灯泡都标有“3V 0.9W”字样,要使两灯泡都能正常发光,以下说法正确的是( )