The Gerúndio form in Portuguese grammar is comparable to the English -ing verb form. This verb form is used to indicate an ongoing action in the present, past or future. In Portuguese, the Gerúndio is formed by adding -ando to -ar verbs and -endo to -er and -ir verbs. Unlike in English, the Gerúndio is not used as a noun. Instead, it expresses a continuing or simultaneous action or provides emphasis in a sentence.