T.Huy XSMB: Gi?i ??c bi?t k?t qu? x? s? Mi?n B?c ???c bao nhiêu v?y m?i ng??i ?i! You may Review a waveform of 1 phase using a waveform of One more section or Look at which has a Earlier calculated waveform on the same examination stage. Webpage 69: Interaction Basic principle: Readings