The police didn't have enough evidence against him. That's the crux of the matter.警察没有足够的证据控告他，这是问题的关键。He said the crux of the matter was economic policy.他说问题的关键在于经济政策。The crux of the matter lies in our lack of expert knowledge.问题的症结在于我们缺乏专业知识。Finding a cheap source of energy is really the crux of the matter.找到一种廉价的能源是真正的关键所在。