把句子的错误找出来,并加以改正.

把句子的错误找出来,并加以改正.
1.It means we shouidnt littering here.
2.Does it mean "Be quiet"?
3.The boy is taking a walk after supper every day.
4.My father is taking a walk aftter supper every day.
5.Look at tjose sign,they are public signs.
6.The flowers are inthe garden look beautiful.