Please don't walk on the gress.

横线在哪里？
如果是这样

Please (don't step) on the grass.

对补充：
gress 改为grass.
既然是这样，我说的就是对了。Please don't step on the grass.

Are you sure it's "gress" not "grass"?

Please don't walk on the grass.写错字了.gress应为grass吧