It There

Note that the pronoun it is often used in English as an impersonal subject or "filler" in expressions concerning weather, time, distance, etc.

Examples:
It is cold today.
It is ten o'clock.
It is a long way from here to Chicago.

It is also commonly used in sentences where the verb to be is fpllowed by an adjective-infinitive construction.

Examples:
It is easy to learn English.
It is impossible to reach him.

We also use there as a subject "filler" in English when we wish to express the existance of a certain object or objects. Thus instead of saying, "A book is on the table," we say, "There is a book on the table." Instead of saying, "Two men are in the room," we say, "There are two men in the room." etc.