24 · Phrases
Auxiliary verbs
An auxiliary verb helps another verb express time, possibility, completion, continuation, or voice. It also determines the form that follows it. In has been repairing, has requires been, and been requires the -ing form repairing.
Has is the finite verb and marks the perfect. It is followed by the participle been. Been marks the progressive and is followed by repairing. The course treats repairing, the verb naming the event, as the head of the verb phrase.
The modal auxiliary can is followed by the plain verb swim.
Supporting did carries the finite contrast while leave remains a plain lexical verb.
Read the verb group from left to right
- Find the lexical verb that names the event.
- Check the form selected after each possible helper: modal plus plain form, have plus participle, or progressive be plus -ing.
- Mark every helper in the chain, including a non-finite one such as been.
A finite auxiliary can usually move before the subject in a question and take not directly. Main-verb be behaves the same way, so these patterns must be considered with the verb group as a whole.
The helper’s spelling is not enough.
Have, be, and do can be main verbs or auxiliaries. When they are auxiliaries, the following verb form reveals the relationship. A modal comes first, followed by perfect have, progressive or passive be, and finally the verb that names the event.
Ten sentences from this lesson, one decision at a time.