Ok, this is a somewhat nonstandard English question. In the Southern US, or at least in Central Virginia, there is an idiomatic use of the phrase *it is* that is equivalent to the expression *there is,* as in

> 
> *It is* not enough gas in my tank to make the trip.
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> 
> 

Not being from the South myself, I'm puzzled by this particular usage. I thought the proper (not to mention, less ambiguous) way to phrase the sentence above was

> 
> *There is* not enough gas in my tank to make the trip.
> 
> 
> 

Compare these two sentences:

> 
> Is it anything for dinner?
> 
> 
> Is there anything for dinner?
> 
> 
> 

How did this expression originate?