I would like to understand more about the part of speech is the word "there". According to Oxford Dictionary, there is describe as an adverb as in the sentence:
'There is a glass."
where "there" is the adverb to the verb "is".
However, often than not, we heard the sentence:
"We are going in there".
I find this sentence seemed ungrammatical as that would indicate that "there" acting as a pronoun for a place that is mentioned before. For example,
"This is the cave. We are going in there."
Even then, I would think that the word "there" redundant, it should be just:
"This is the cave. We are going in."
So I would appreciate if anyone can enlightened me on the correct usage of this word in the above cases.
Just on one simple example, I'm going to show you the difference:
There is a glass there. where the first there is a pronoun (the so-called existential there) and the other there is an adverb.