and modal verbs Find out how to use key verbs for different tenses. Common verb forms used in French are auxiliary verbs, expressions with avoir and être and modal verbs. The perfect tense with ...

The grammatical category of tense in English is a bipolar relation based on the ... If a sentence does not contain the auxiliary verb be plus a verb with the suffix '-ing' it is [-Prog]. [+Prog] ...

The one thing the two words have in common is their function; which is, they act as auxiliary verbs. Otherwise also known as helping verbs, auxiliary verbs add functionality to main verbs.