It, that, this

Please read:

We’ve been having trouble getting staff.

So, I don’t like to use “Am I right” but I write as follows:

1.The subject of “getting” is we. Is this right?
2.The subject of “getting” is we. Is that right?
3.The subject of “getting” is we. Is it right?

Do you think in this case, this, that and it are interchangeable and (1),(2), (3) have the same meaning? If not, how to distinguish these 3 words?



This and that are so called demonstrative adjectives. This indicating the one here, that indicating the one there and it is the impersonal pronoun. In your sentences all three are acceptable.