Wattful
有功的, 與電壓同相的
??? 情景例句
I haven't got anything to do now; I'm so bored.
我現在無事可做，感覺很無聊。
Don't tell anyone that I did it.
別說是我做的。
Could you tell me your secret for a long, happy life?
你能告訴我長時間地過著快樂的生活的秘訣嗎？