求助！！实在不知道哪错了~！

#include <iostream>
#include <string>
using namespace std;
class Teacher
{
   public:
      Teacher(string n,int a,string t)          //基类的构造函数
      {
        name=n;
        age=a;
        title=t;
      }
      void display_1();
   protected:
      string name;
      int age;
      string title;
};
void Teacher::display_1()
{
   cout<<"姓名："<<name<<endl;
   cout<<"年龄："<<age<<endl;
   cout<<"职位："<<title<<endl;
}
class Student
{
   public:
      Student(string m,string x,int s)
      {
         namel=m;
         sex=x;
         score=s;
      }
      void display_2();
   protected:
      string namel;
      string sex;
      int score;
};

void Student::display_2()
{
   cout<<"姓名："<<namel<<endl;
   cout<<"性别："<<sex<<endl;
   cout<<"成绩："<<score<<endl;
}

class Graduate:public Teacher,public Student               //多重继承派生类的构造函数
{
   public:
      Graduate(string n,int a,string t,string m,string x,int s,string ad):
      Teacher(n,a,t),Student(m,x,s),addr(ad){}
   private:
      string addr;
}

错误就出在这个派生类的构造函数上面~小弟找了一晚上实在不知道哪错了~！！
请各位指点一下小弟~！程序代码可以直接运行，会提示错误，哪个错误的类型小弟也不知道是什么意思~！
52 expected unqualified-id at end of input
52 expected `,' or `;' at end of input
这是错误详细信息，请大家帮帮忙呀~！