not know/not be able to tell one end of sth from the other
释义
●not know/not be able to tell ˌone end of sth from the ˈother (informal) know absolutely nothing about sth, for example a machine对（机器等）一无所知◆Don’t ask me to fix the car. I don’t know one end of an engine from the other. 别让我来修车，我对发动机一窍不通。