hi,guys,who can help me to understand that sentence?

hi, guys. who can help me?

I just don't know what it means.

fences are actually retaining walls that step up to front sliding door.

what does that sentence mean?

as you know, a person tells me that means adding retaining walls. is it true?

I am just puzzled.

who can help me?

I think what is sentence is true.

The fences are very useful in places where there are many persons trying to pass through a single door.

I think what is sentence is true.

The fences are very useful in places where there are many persons trying to pass through a single door.

I think what is sentence is true.

The fences are very useful in places where there are many persons trying to pass through a single door.

so what do you think of "step up to"

is it equal to add?

that sentence doesn't make sense…

why?

Walls are usually thought of as something that is solid, as they are usually made of stone or bricks, and are bonded together by a cement mixture or mortar – like the Great Wall of China .

Fences are generally made of wooden posts or planks, or even concrete posts. Sometimes, barbed wire may be strung between the posts.

A hedge is a line or row of plants and bushes, It can also be used to mark the boundary of a piece of land.

http://dictionary.cambridge.org/define.asp?key=88920&dict=CALD

http://dictionary.cambridge.org/define.asp?key=28466&dict=CALD

http://dictionary.cambridge.org/define.asp?key=36495&dict=CALD

It is nonsense. It could mean any number of absurd things. It is not a sentence. It is a bunch of random words put together.

it doesn't make sense to me, either. especially the second part "that step up to front sliding door."

something is missing in the sentence;