A preposition connects a noun or pronoun to the rest of the sentence.
A preposition can tell the relationship of a train to the tracks.
EX: on the tracks, above the tracks, below the tracks
To find the object of the preposition, ask "whom?" or "what?" after the preposition.
EX: on the tracks
On the what? tracks
Tracks is the object of the preposition (OP)
A adj SN V adv P A OP
The freight train raced quickly down the tracks.
aboard, about, above,
across, after, against,
along, among, around, at.
in, inside, into,
like, near, of, off,
on, out, outside, over.
before, behind, below,
beneath, beside, between,
beyond, but, by.
past, since, through,
throughout, to, toward.
down, during,
except, for, from.
under, underneath,
until, up, upon,
with, within, without.