________,he couldn't solve the problem. So he turned to his friend for advice.
A:Try as he might
B:As he might try
C:He might as try
D:Might he as try
如图是电阻R的I﹣U图象,图中α=45°,由此得出( )
将标有“220V 100W”的灯泡接入电压为110V的电路中,灯泡的实际功率是(不考虑温度对电阻的影响)( )
①AF⊥PB;②EF⊥PB;③AF⊥BC;④AE⊥平面PBC;⑤平面PBC⊥平面PAC.其中正确命题的序号是____.