直接看例子就好：

#include "qdatetime.h"class Person {public:    Person(QString name, QDate birthdate)    QObject(name.ascii()),    m_Birthdate(birthdate) {}    Person(const Person& p) : QObject(p),    m_Birthdate(p.m_Birthdate) {}private:    QDate m_Birthdate;};class Student : virtual public Person {       1    // other class members};class Teacher : virtual public Person {       2    // other class members}class GraduateTeachingFellow :    public Student, public Teacher {          3public:    GraduateTeachingFellow(const Person& p,                           const Student& s, const Teacher& t):    Person(p), Students(s), Teacher(t) {}     4

	Note keyword virtual here.
	virtual inheritance.
	virtual not needed here.
	It is necessary to initialize all virtual base classes explicitly in multiply-derived classes, to resolve ambiguity about how they should be initialized.

Each instance of a class that virtually inherits from another has a pointer (or a variable offset) to its virtual base class subobject. 看来这里每个虚继承类的实例代表的是Student和Teacher都会有一个指针指向虚基类的 virtual base class subobject。具体这里怎么翻译还得查查