In old China there was hardly any machine-building industry, leave alone an automobile industry.在旧中国几乎没有机器制造工业，更不消说汽车制造业了。He was too much an invalid to leave alone.他病得太重，不能没人陪着。What a strange thing that she and I ever came to meet, leave alone to marry.我同她会碰在一起已是够奇怪的，更不要说结婚了。He will leave alone things that might cause trouble.他从来不碰会招惹是非的事。