impossibility

impossibility后面接of和动名词，不接不定式，如可以说the impossibility of being in two places at once，不可说the impossibility to be in two places at once。可以说the impossibility of his doing this，不可说the impossibility for him to do this。It is an impossibility to do this是可以说的，但注意这里的to do this指第一词It，跟impossibility没有关系。