九月で彼女と知り合ってまる一年経つことになる。

September

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

she; her; her; girlfriend; sweetheart

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

to get to know (someone); to make acquaintance

circle; entirety; whole; full; complete; money; dough; moola; enclosure inside a castle's walls; soft-shelled turtle; suffix for ship names; suffix for names of people (esp. infants); suffix for names of swords, armour, musical instruments, etc.; suffix for names of dogs, horses, etc.

one; best; first; foremost; beginning; start; bottom string (on a shamisen, etc.)

year; many years; age; past one's prime; old age

to pass; to lapse

thing; matter; incident; occurrence; event; something serious; trouble; crisis; circumstances; situation; state of affairs; work; business; affair; after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to; nominalizing suffix; pretending to ...; playing make-believe ...; alias; aka; nickname; alternative name; also known as

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to become; to get; to grow; to be; to reach; to attain; to result in; to prove to be; to consist of; to be composed of; to succeed; to be complete; to change into; to be exchanged for; to play a role; to be promoted; to do ...