Why when I write dosbox in 1000:0021 can't not write thank you bosses when

1000 - d: 0
1000:0000 B8 01 00 8 D8 A1 00 00-8 b e 1 e 01 00 89 D8 A1 00
1000-0010, 00 8 b e 02 1 00 D8 03 01-06 00 04 B8 00 00 A0 02

- a 0-0 draw 1 f
60, 0000-0000 10, 00 00 00 00 F0 08 70-08 70 00 00 00 70
08, 0000-0010 00 70 00 00 00 F0 10 to 60 60 10 F0 60 10, 00 F0
- a 1000-0
1000:0000 mov ax, 1
Mov, 1000-0003, ds, ax//ax=0001 ds=0803
1000:0005 moy ax; [0]//AX=0008 DS=0001, 0001:0=the value of 0000-0010, 0008 to AX
Mov bx, 1000:0008 [1]//bx=7000
1000:000 c mov ax, bx//ax=7000
1000:000 e mov ax, [0]//ax=0008
1000:0011 mov bx, [2]//bx=0070
1000:0015 add ax, bx//ax=0078
The add ax, 1000-0017, [4]//ax=1060 + 0078=10 d8
Mov ax, 1000:001 b//ax=0, 0000
1000:001 e mov al, [2]//AX=0070
1000:0021 mov bx, 0//bx=0000
1000:0024 mov bl, [c]//BX=0060
Add 1000-0028, al, bl//AX=0000 + 0070 + 0060=00 d0
1000:002 a