把句子中的错误找出来,并加以改正.

问题描述:

把句子中的错误找出来,并加以改正.
1、He walks to the book and picks up it.
2、Ron is only seven year old.
3、The signs on the bird's cage is interesting.
4、He can see a lot public signs in the park.

1.picks up it改成picks it up
2.year改成years
3.on改成in
4.a lot后面要加介词of