一直以为to+动词都是不定式，但是查了朗文辞典，才发现不是这样的。例如：朗文p1624:9 in connection with 对...，关于...,
There's always an element of risk to starting a new business.创业总要担点风险。我认为相当于: 介词(to)+名词(verb+ing)