Which of the following is a similarity between the verbal phrases "ir a" and "acabar de"?
They both follow the double verb rule even though there is a preposition in the middle, so the next verb always remains in the infinitive.
Neither of them ever need to be conjugated because the verb that follows the phrases is always conjugated instead.
Both of these phrases are only used in Latin America and neither would be heard, used, or understood in Spain.
They are both synonyms.