Verb forms can be classified as either simple or compound. A simple verb form is made up of a single word, whereas compound forms require the addition of one or more other verbs to make the meaning clear. In a compound verb, any such ‘extra’ verbs are known as ‘auxiliary’. Auxiliary verbs are also sometimes known as ‘helper verbs’ – because they help to provide another verb with a shade of meaning that it cannot represent using any of it’s own (simple) forms.
In English, we use compound verbs a lot more than the Portuguese do. For example, when we use verbs negatively, we have to use the auxiliary verb ‘do’ (eg. ‘I do not think’, ‘they do not eat’). We have already seen how the verb ‘to go’ can be used as an auxiliary to refer to the future. Sometimes you can use several auxiliary verbs together to provide greater precision (a somewhat convoluted example: ‘He would have had to have been going’).
The verb that is being ‘helped’ by an auxiliary is used either in its infinitive form, or in a form known as a ‘participle’ – this is true in both English and Portuguese. A participle is a word derived from a verb that can also be used as an adjective. There are two types of participle, known as the present participle, and the past participle. Not surprisingly, present participles refer to an action or description that is current or ongoing, whereas past participles refer to completed actions or descriptions. There is no such thing as a ‘future participle’, because we can also use present and past participles to talk about the future. Try not to let that disturb you! We will come back to participles later.