курсовая остался один баг не могу исправить

uses crt,graphabc;
label mn;
var a:array[1..10] of string;
k,k1,k3,img,z,z1,a1,b,c,d,e,f2,g,h,i,j,k2,l,m,n,o,p,q,r,s2,t:integer;
s,s1:string;f:text;
procedure menu(x,y,n:integer;var k:integer);
var i:integer; c:char;
begin
setWindowWidth (580);
setWindowHeight(540);
setbrushstyle(bsclear);
k:=1;
repeat setfontstyle(fsnormal);    setfontsize(20);SetFontName('Arial');
for i:=1 to n do
begin
if  i=k then setfontcolor(clgreen)
else setfontcolor(clred);
textout(x,y+30*i, a[i]);
end;
c:=readkey;
if c=#80 then k:=k+1; if k>n then  k:=1;
if c=#72 then k:=k-1; if k<1 then  k:=n;
until c=#13;
setfontcolor(clblack);
end;
Begin
hidecursor;
setfontsize(20);
clearwindow;
repeat
mn:clearwindow;
a[1]:='';
a[2]:='теория';
a[3]:='';
a[4]:='';
a[5]:='выход';
menu(140,130,5,k);
setfontcolor(clMaroon);
case k of
2:begin
hidecursor;
clearwindow;
setfontsize(20);
a[1]:='проез';
a[2]:='рег';
a[3]:='нерег';
menu(100,150,3,k3);
case k3 of
1:begin
setWindowWidth (700);
setWindowHeight(400);
clearwindow;
hidecursor;
clearwindow;
setfontsize(10);
assign (f,'139.txt');
reset(f);
while not eof (f) do
begin
readln (f,s);
writeln(s);
end;
close(f);
setfontsize(20);
repeat
until readkey=#13;
end;
2:begin
setWindowWidth (700);
setWindowHeight(400);
clearwindow;
hidecursor;
clearwindow;
setfontsize(10);
assign (f,'140.txt');
reset(f);
while not eof (f) do
begin
readln (f,s);
writeln(s);
end;
close(f);
setfontsize(20);
repeat
until readkey=#13;
end;
3:begin
setWindowWidth (700);
setWindowHeight(400);
clearwindow;
hidecursor;
clearwindow;
setfontsize(10);
assign (f,'145.txt');
reset(f);
while not eof (f) do
begin
readln (f,s);
writeln(s);
end;
close(f);
setfontsize(20);
repeat
until readkey=#13;
end; end; end;
5:closewindow;
end;
textout(10,300,s);
setfontstyle(fsnormal);
until keypressed;
end.