“Along” is a preposition (of movement and position) and an adverb.
Here are examples – as an adverb:
- Sanchez was running along besides Mr. Zapatero (el Señor Sanchez iba corriendo al lado del Señor Zapatero).
- Merkel will be along in a couple of minutes (dentro de un par de minutos viene la Señora Merkel).
- We are going to the opera. Why not come along with us? ¿Por qué no vienes con nosotros?
- Come along! (¡venga!). It is time to leave.
This form of the adverb does not have an equivalent in Castellano (no tiene equivalente en castellano: se usa verbos de movimiento).
Now as a preposition:
- Figaro and Susanna went for a walk along the river (Figaro y Susana fueron a dar un paseo por el río).
- The trees along the river are beautiful (los árboles a lo largo del río son hermosos).
- The cafe is along here (… está por aqui).
