Tra. Trans. Preter.
"Tra" means "through", as "Tra la truo", Through the hole. "Tra la
mondo", Through the world.
"Trans" means "at the other side, across", as "Li logxas trans la
rivero", He lives on the other side of the river. With the accusative it
means "to the other side", as "Li nagxis trans la riveron", He swam to
the other side of (across) the river.
"Preter" means "past, by", or "beyond;" it conveys the idea of coming
up from behind and passing on in front, as "Mi pasis preter via frato",
or "Mi preterpasis vian fraton", I passed your brother. The difference
between "tra", "trans", and "preter" is clearly shown by the sentence
"Trapasinte la arbaron, li preterpasis la pregxejon kaj tiam transpasis
la riveron per la ponto", Having passed through the wood, he passed by
the church, and then passed over the river by the bridge.