9 ÷9+ 9 +（9×9 -9+ 8）÷ 8 +8 -8 +8 -8=20
(9+9+9+9+9)÷9-(8+8-8)÷8+8+8=20
9+9+9-9+9-9+8-8+8÷8+8÷8=20
99+99/99-（88+（8-8）*8-8）=20
