【正确答案】P wave: atrial depolarization (2`); QRS complex: depolarization of ventricles (2`); T wave: repolarization of ventricles (2`); PR interval is the interval from the beginning of atrial activation to the beginning of ventricular activation (2`); QT interval is required for ventricular depolarization and repolarization. (1`); ST-segment: potential of myocardial cell in each part of ventricle is equal to each other and located at the platform period of AP (1`).