Two other common verbs are also used non-systemically.

Acabar

Acabar (“to finish,” “to end”) is used in the present tense, followed by de + infinitive, and translates as “to have just done something”:

As with hace when combined with a present tense verb, the present tense equals present perfect meaning in the above example.

Just as we saw when hacía combines with a past tense verb, usually the imperfect, the imperfect tense of acabar equals past perfect meaning:

Llevar

The verb llevar plus duration of time often translates as a form of “to be” and when combined, as it often is, with a present participle, means “to have been doing (something)”:

The first example above is merely another way of expressing Hace cinco años que vivo en este pueblo deprimente.

Likewise, llevar is used in the same circumstance but in the imperfect tense and translates as “had been” (past perfect tense) or, with the present participle, “had been doing” (something):

Desde = since

As is often the case in English, the mere inclusion of the word desde (“since”) in a sentence with a present tense verb normally renders the meaning to be present perfect. Likewise, when desde appears in a sentence in the imperfect tense, the meaning routinely shifts to past perfect tense.