Auxiliary verb list

Auxiliary verbs, also called helping verbs, support main verbs to build tenses, voices, questions, and negatives. English uses two types: primary auxiliaries and modal auxiliaries. The primary set—be, have, and do—combine with participles or base forms to form continuous, perfect, and emphatic structures, and to make questions and short answers. Modal auxiliaries—will, would, can, could, may, might, shall, should, must, ought to, and used to—express meanings such as ability, permission, obligation, advice, likelihood, and habitual past. Modals don’t take -s for third-person singular and are followed by a bare infinitive. Mastering auxiliaries increases precision and flexibility in speech and writing.

Primary auxiliaries

Primary verbs	be	have	do
-s form	is	has	does
Past form	was/were	had	did
Past participle	been	had	done

Modal auxiliaries

Modal verbs
will	can	may	shall
would	could	might	should
must	ought to	used to