A member function of a derived class has a different return type from the correspondingmember function of the base class.
派生类的成员函数与相应的基类成员函数有不同的返回类型。
2
To implement an interface member, the correspondingmember on the class must be public, non-static, and have the same name and signature as the interface member.
若要实作介面成员，对应的类别成员必须是公用、非静态，而且具有与介面成员相同的名称和签章。
3
A matching work item is either a user work item corresponding to the caller principal name, or a group work item corresponding to one of the groups of which the caller is a member.