This is as much meant as an indirect answer to this question, as it is to answer some other of your questions (this one and this one), since they all seem to follow the same pattern of asking how to translate something into FOL.
FOL is in itself a really nice and solid logic to work with. It is especially powerful for doing mathematics. However, to capture the intricacies of natural language, pure FOL is often woefully unsuited.
There are many linguistical logics out there, each having their own purposes, bringing their own solutions to linguistical problems and having problems of their own in expressing them. To name a few prominent logical systems in linguistics, you could take a look at Montague grammar, intensional logic, modal logic or fuzzy logic.
So instead of asking "how to translate this and that sentence of natural language into first-order logic?", perhaps the right question ought to be "is first-order logic suitable to adequately express this and that?"
The answer to this last question in the context of translating "it" is: no, FOL is not adequate to express how we use the word "it" in natural language.
If you are really interested in linguistical semantics, I recommend reading "Logic, Language and Meaning" from L.T.F. Gamut (which is a collective pseudonym)