早知文理百科

fallv.落下；下落；掉落；突然倒下；n.(雪、岩石等的)降落;发生;秋天（AmE=autumn） There is still a risk that the whole deal will fall through. 整桩买...

risk是可数名词。 riskn.危险；风险；危险人物；会带来风险的事物； v.使…冒风险(或面临危险) You have no right to take risks with other people\'s lives...