1 The Preposition a

The preposition a expresses movement, it may be spacial (in space) or in time. Generally, it denotes a certain tendancy. It proceeds the I.C (Indirect Complement) in the sentence and on determined ocasions the D.C (Direct Compliment).

It can also express final values, causative (said/saying of a subordinate sentence: that expresses the cause of the saying or of the saying or the fact that it is said), distributives (conserning distribution), the indication of the starting of an action (for example: to flower - florecer), imperatives, modals (relates to the mood of the verb), instrumentals (the thing that principally indicates the meaning of the relationship) and conditionals.

Some Spanish verbs are always accompanied by a and the masculine definite article el

a + el = al

1.1 Espacial (location in space)

or they involve a determined direction:

In the second, it's almost always about verbs verbs of location/situation or presence [to be present]:

or verbs of motion with the sense of restricting to establish a distance:

1.1.1 Movement, Direction, Destination

In these cases, a expresses a value contrary to de and desde, and a similar value to hacia:

Juan miró a su izquierda
[opposed to Juan miró desde la izquierda]:

Also with a metaphoric value, as in the following cases, where an activity resembles a place.

1.1.2 Fixed or Relative Location, Distance

It involves at least two elements between those that establish a relationship that depending on the case, may/can be absloute or relative.

In such cases such as the following, the direction also expresses a location with a subtle difference in meaning, that can be less/smaller/lower, like here:

Although in both cases there's a referential element, in the first "(al norte" - "to the north" of where we are). We can get around it, converting it in one place (in Alaska for example); not like this in the second case, where it can't do without any of the related terms

"A" also denotes an interval or distance between two elements, almost always in constructions with "de" and "desde". In these cases, it's the equivelant to "hasta":

1.2 Ubicación Temporal - Temporary Location/Situation

The preposition a introduces the majority of temporary phrases that involve a fixed/definate measurement of time (times and dates).

It also appears in specific set phrases relating to the idea of what took place (times and dates).

And, as in the case of those having a spacial value it means a closed cycle, nearly always in constructions with de:

It aquires a similar value as por(English a day/week/month/year) in phrases that express the regular occurance of an event:

1.3 Proceeding the Direct and Indirect Compliments

The preposition a introduces the Direct Compliment when followed by a living object and may not always have an Indirect Compliment introduced by a (in such circumstances it takes para before the Indirect Compliment):

The Indirect Compliment usually introduced/proceded by a, although if it's refering to a Personal Pronoun it's proceded by para

Mandé flores a Silvia [para Silvia]
Dejaron esas maletas para ustedes
Lo trajo para mí

1.4 Finality and Causative Values

A indicates finality in certain cases, almost always constructed with the infinitive, with a similar value to para:

In exchange a + el (al) implies the opposite/contrary, the cause or motive moves the action:

The construction, as in the previous examle, sometimes has a very visible temporary nuance:

And on occasions it displaces (moves) for example the causative value, involving only a temporary indicative.

1.5 Distributive Values, Price

When a quality indicated by distributive proportion or establishes/indicates a relationship in connection with (about) price or value of something, it's preceded by a:

1.6 Beginning of an Action (precio incoativo) and Imperative value

With the affirmative, a can indicate (as well as cause and consequence), the beginning of an action:

A su vez, constructions like the following having an imperative value or admonitory (a piece of advice that is also a warning to someone about their behaviour), they strongly encourage to carry out/achieve/fulfil a determined action.

One very particular use is the a for introducing the idea of a challenge or a bet. Wigh an interrogative character, it adds a certain assurance/confidence beforehand in the response/answer, as if we might possibly/might have said "seguro que/surely"

1.7 Modal and Conditional Values.

Although less common/frequent, determined constructions with a indicate the way in -sometimes "el medio por - halfway through"- that realises an action. It's almost always set phrases that adopt this value curcumstantially:

The same occurs with certain conditional uses/usage:

The instrumental value, in exchange, is much more frequent:

1.8 Verbs that require (demand) a

Specific (definate) verbs require the use of the preposition a. Others use in the (immense) majority of cases, are accompanied by the/this preposition. These are some of the most frequent: