手机没电关机:
1) be powered off: power此时为动词
2) be out of power: power此时为名词
The phone you are calling is powered off.
您所拨打的电话已关机
3) My phone is dead. / My phone died.
die,死亡,动词
dead,形容词,死了的
我手机没电了,我需要充一下电。
My phone is dead. I need to charge it.
(charge:充电)
没接到你的电话真是太抱歉了,我手机没电了。
I am really sorry I didn't get your call. My phone died.