Пжадуйста помогите перевести и разобраться пункт 11.2/4 draft стандарта.

11.2/4 A base class B of N is accessible at R, if
— an invented public member of B would be a public member of N, or
— R occurs in a member or friend of class N, and an invented public member of B would be a private or protected member of N, or
— R occurs in a member or friend of a class P derived from N, and an invented public member of B would be a private or protected member of P, or
— there exists a class S such that B is a base class of S accessible at R and S is a base class of N accessible at R.