
knockon敲(门、窗等);撞knockat敲(门,窗等)Knockonthedoorbeforeyouenter.进屋之前要先敲门。WhenIfellIgotaterribleknockonthehead.我摔倒时头撞得很厉害。Hegotanastyknockonthehead.他头部遭到重重一击。DidIhearaknockatthedoor?是有人敲门吗?Iwaswakenedbyaknockatthedoor.敲门声把我吵醒了

knockon敲(门、窗等);撞knockat敲(门,窗等)Knockonthedoorbeforeyouenter.进屋之前要先敲门。WhenIfellIgotaterribleknockonthehead.我摔倒时头撞得很厉害。Hegotanastyknockonthehead.他头部遭到重重一击。DidIhearaknockatthedoor?是有人敲门吗?Iwaswakenedbyaknockatthedoor.敲门声把我吵醒了