为什么SQL两个表建好了外键，关系图却没连接在一起

create database School_MS
use School_MS
go
create table Student
(
Sno char(8) not null primary key,
Sname varchar(8) not null,
Sex char(2) check(Sex=‘男’ or Sex=‘女’),
Birthday Smalldatetime check(Birthday >='1990-01-01’and Birthday<= ‘2010-12-31’ ),
Dno char(6),
Home varchar(40),
Tel varchar(40),
Entime Smalldatetime,
Classno char(4) not null unique,
)

create table Course
(
Cno char(4) not null primary key,
Cname char(20) not null,
Experiment tinyint,
Lecture tinyint,
Semester tinyint,
Credit tinyint
)

create table Teacher
(
Tno char(8) not null primary key,
Tname char(8),
Sex char(2) check(Sex=‘男’ or Sex=‘女’),
Birthday smalldatetime,
Dno char(6),
Pno char(4),
Home varchar(40),
ZipCode char(20),
Tel varchar(40),
Email varchar(50)
)

create table Class
(
Classno char(4) not null primary key,
ClassName char(8) not null,
Num int,
Charge char(4),
foreign key(Classno) references Student(Classno)
)

create table StudentCourse
(
Sno char(8),
Cid char(4),
Score tinyint,
primary key(Sno,Cid),
foreign key(Sno) references Student(Sno),
foreign key(Cid) references Course(Cno)
)

create table TeacherCourse
(
Tno char(8) not null,
Classno char(4) not null ,
Cno char(4) not null ,
semester char(6),
SchoolYear char(10),
ClassTime varchar(40),
ClassRoom varchar(40),
primary key(Tno,Classno,Cno),
foreign key(Tno) references Teacher(Tno),
foreign key (Classno) references Class(Classno),
foreign key(Cno) references course(Cno)
)
请教下大神，到底要怎样修改代码才能把Teacher表中的Tno和TeacherCourse表中的Tno连在一起呢，
第一次发文章，如果发的格式不见，望大家见谅额