Pitman's Commercial Spanish Grammar (2nd ed.)

Prepositions join words together to mark certain relations between them.

The principal prepositions are --

Á (at, to)
Ante (before -- in point of place)
Bajo (under)
Con (with)
Contra, en contra de (against)
De (of, from)
Desde (since, from)
En (in)
Entre (between, among)
Hacia (towards)
Hasta (till, as far as, even)
Para (for the purpose of, for, in order to)
Por (for, by, because of)
Según (according to)
Sin (without)
Sobre (upon)
Tras, tras de (behind)
Para con (una persona),[164] (towards, with, a person)

Footnote 164: "Fué muy generoso para conmigo": He was very generous with me.

Many verbs take in Spanish a different preposition than in English. Some verbs take a preposition in one language and none in the other, as --

Depender de una promesa: To depend on a promise.
Convenir en una transacción: To agree to a compromise.
Confiar en un desconocido: To trust a perfect stranger.
Regalarle un cheque: To present him with a cheque.

The use of the correct preposition according to the verb it follows is best learnt by practice. In the second part of the grammar, the student will be helped with a list of the most characteristic differences between the two languages. The Spanish construction is not quite so rigid in this respect as is the English.

Difference between de and desde both translating "from" -- De mark the origin only, as --

Esta seda viene de Italia: This silk comes from Italy -- it is Italian silk.

Desde calls attention to distance of time or space, as --

Desde el 1° de Enero se estableció en comercio por cuenta propia: From the 1st of January, he started in business on his own account.

He viajado desde Londres hasta Calcuta en tantos días: I traveled from London to Calcutta in so many days.

The chief difficulty in the employment of the Spanish prepositions is the use of Por and Para --

Por is used --

1. To denote agency = by[165]; as --

Es tenido en gran cuenta por sus amigos: He is thought much of by his friends.

Este establecimiento fué fundado por mi bisabuelo: This establishment was founded by my great-grandfather.

Footnote 165: After the passive voice of verbs denoting mental action when formed by ser, Por is elegantly substituted by De, as: Son amados por or de sus padres (they are loved by their parents). But: Se aman por sus padres.

2. To denote the motive of an action, as --

Lo hizo por envidia: He did it for (out of) envy.

3. To denote equivalency of any kind, as --

Cinco peniques por libra: Fivepence for a pound -- per pound.

Trocar un producto por otro: To exchange one product for another.

Considerar á uno bueno por £1,000: To consider somebody as good for £1,000.

Por mejor le envié yo como viajante: I sent you to travel, holding you for a better man.

Tienda por tienda, prefiero esta: Of the two shops I prefer this.

4. To denote distribution, as --

Vinieron cinco por cinco: They came five by five.

Para is used --

1. To denote the object of an action (generally "to" or "in order to"), as --

Trabajo para ganarme la vida: I work to (in order to) earn my living.

2. To denote destination (or direction), as --

El tren sale para Valencia: The train leaves for Valencia.

Esta cédula es para el Sr. Fulano: This warrant is for Mr. So-and-So.

Voy para casa: I am going towards home.

Many idiomatic uses of Por and Para must be learnt by practice.