The word there firstly functions as an adverbial. For example, consider the following two sentences:
- I am studying in the library.
- We are studying there, too.
In the first sentence, the prepositional phrase in the library functions as an adverbial that indentifies in what place I am studying. In the second sentence, the pronoun there replaces the prepositional phrase in the library but also performs the function of adverbial.
However, the word there also functions existentially. Take, for example, the following two sentences:
- A girl from Nantucket exists.
- There is a girl from Nantucket.
In the first sentence, the noun phrase A girl from Nantucket functions as the subject and the verb exists as the predicate. In the second sentence, the pronoun There functions as the subject, the verb is as the predicate, and the noun phrase a girl from Nantucket as the subject complement.
However, unlike in the case of the pronoun there functioning as an adverbial, the existential there in There is a girl from Nantucket lacks an antecedent. An antecedent is the word, phrase, or clause that a pronoun replaces. Instead, existential there acts as a grammatical subject filler in sentences that make statements about the existence of someone or something. For example:
- A woman who has one daughter exists. ~ There is a woman who has one daughter.
- A boy was in my class. ~ There was a boy in my class.
- Do some problems with your car exist? ~ Are there some problems with your car?
Note that existential there may take either a singular or plural verb depending on the grammatical number of the subject complement. The verb that follows existential there may also take any tense or aspect conjugation including the simple present, present perfect, simple past, and past perfect.
Related to existential there, dummy it also lacks an antecedent.
Dummy it is firstly used in sentences pertaining to time and weather. For example:
What time is it?
It is five o’clock.
It is time to leave.
It is snowing.
It is going to sleet.
It might rain.
Dummy it is secondly used in extraposition or cleft sentences. Extraposition is defined as the movement of a grammatical constituent from its normal place to a place at the end or near to the end of a sentence. Extraposition often results in the creation of subordinate noun clauses. For example:
- Espen seems to be hungry. ~ It seems that Espen is hungry.
- Washing your hands is necessary. ~ It is necessary that you wash your hands.
- That you drive slowly on ice is recommended. ~ It is recommended that you drive slowly on ice.
Dummy it is thirdly used as dummy objects in indefinite constructions to refer to vague or general things. For example:
- Take it easy!
- Can you make it to the party?
- This is it!
For information related to existential their and dummy it in English, please refer to (1) The Indefinite English Pronouns for ESL Students, (2) The English Personal Pronoun System for ESL Students, and (3) The Formation and Use of the Subjunctive Mood in English here on Bright Hub Education.