Auxiliary verbs work with a main verb to build questions, negatives, and many compound verb forms. They do not carry the main meaning by themselves in these patterns. In English, the main verb gives the core idea, while the auxiliary helps show tense, aspect, voice, or sentence type. A sentence can also use more than one auxiliary: has been waiting, will be finished, is being repaired. This pattern depends on the verb system in Verbs and on tense forms such as Present Simple, Present Continuous, Present Perfect, and Past Simple.

Core functions of auxiliary verbs

Usage	Explanation	Example
Question making	Auxiliaries help form questions by carrying the tense and agreement details for the sentence.	Do you like spicy noodles?
Negation	Auxiliaries help form negative statements by joining with not or a negative contraction.	She is not ready yet.
Complex tense building	Auxiliaries help build longer verb forms by working with a main verb instead of replacing it.	We have finished the report.

When a question does not use be or another auxiliary, English uses do, does, or did. The structure is auxiliary + subject + main verb in the base form. Do you work here? Does she like coffee? Did they call yesterday? The main verb stays in the base form, so it is work, like, call, not works, likes, or called in the question form. In everyday speech, this pattern appears with most action verbs, including questions in Present Simple and Past Simple.

Do support in present and past questions

Verb	Subject	Infinitive	Conjugation	Example
do	I	ask	do ask	Do ask before you borrow the book.
do	you	ask	do ask	Do you ask for help when the map is unclear?
does	he	ask	does ask	Does he ask smart questions in class?
does	she	ask	does ask	Does she ask about the ingredients first?
did	we	visit	did visit	Did we visit the gallery last week?
did	they	finish	did finish	Did they finish the puzzle in time?

Scramble

Negative sentences use do not, does not, and did not when the main verb is not be or another auxiliary. The usual form is subject + auxiliary + not + main verb in the base form. I do not know. She does not drive. They did not wait. Spoken English often uses contractions: don’t, doesn’t, and didn’t. The main verb keeps its base form after the negative auxiliary, so the sentence is He doesn’t speak French, not He doesn’t speaks French. This pattern is central to Negatives.

Do support with not in negatives

Verb	Subject	Infinitive	Conjugation	Example
do	I	agree	do not agree	I do not agree with that idea.
does	he	like	does not like	He does not like cold coffee.
did	we	hear	did not hear	We did not hear the announcement.
do	you	need	do not need	You do not need an umbrella today.
does	it	fit	does not fit	The lid does not fit the jar.
did	they	win	did not win	They did not win the raffle.

Scramble

The verb be combines with an -ing form to make continuous tenses: am/is/are + -ing in the present and was/were + -ing in the past. I am reading. She is cooking. They are waiting. We were driving home. The -ing form shows an action in progress, and be carries the tense. With a longer verb phrase, be still comes before the -ing verb: is being repaired, was working, are studying. The pattern appears in Present Continuous and other progressive forms.

Be forms in continuous tenses

Subject	Infinitive	Conjugation	Example
I	read	am reading	I am reading by the window.
you	cook	are cooking	You are cooking something delicious.
he	swim	is swimming	He is swimming at the hotel pool.
she	paint	is painting	She is painting a bright mural.
we	wait	are waiting	We are waiting for the train.
they	travel	are traveling	They are traveling across Spain.
I	sleep	was sleeping	I was sleeping when the phone rang.
you	laugh	were laughing	You were laughing at the joke.

Scramble

Have combines with a past participle to form perfect tenses: have/has + past participle in the present perfect and had + past participle in the past perfect. I have finished. She has arrived. They had left. The past participle usually follows the form of have directly, and the whole structure points to an action completed before another time, or to a past event with a result that still matters now. In Present Perfect, the link is often to the present. In had + past participle, the link is to a later past moment. Examples include has gone, have seen, and had started.

Have forms in perfect tenses

Subject	Infinitive	Conjugation	Example
I	finish	have finished	I have finished my homework.
you	lose	have lost	You have lost your keys again.
he	write	has written	He has written a short story.
she	choose	has chosen	She has chosen the blue notebook.
we	see	have seen	We have seen that movie already.
they	arrive	had arrived	They had arrived before the rain started.

Scramble

In the passive voice, be + past participle puts the focus on the subject that receives the action. The doer may appear in a by phrase, but it is often omitted. The window is broken. The tickets were sent yesterday. The house is being painted. The form of be changes for tense, while the past participle stays after it. Compare Someone broke the window with The window was broken. English uses this structure when the result, event, or affected thing matters more than the person acting. The passive pattern is common in formal writing and in sentences shaped by Punctuation and Direct Speech.

Passive voice with be plus participle

Usage	Explanation	Example
Unknown agent	Use be plus past participle when the action matters more than who did it.	The tickets were printed this morning.
Focus on the receiver	Use be plus past participle to put the subject in the spotlight as the thing affected.	The cake was eaten quickly.
Formal or neutral style	Use be plus past participle when you want a calm, factual tone.	The report is reviewed every Friday.

Modal verbs such as can, could, may, might, must, should, would, and will are followed by a base verb. The structure is modal + base form: can swim, should leave, will call, might rain. Modals do not take -s in the third person, so it is she can go, not she cans go. They also do not use do-support for questions or negatives: Can you help? She must not enter. Many modals express ability, possibility, advice, necessity, or future meaning, and they often appear with the simple forms taught in Present Simple.

Modal verbs followed by base form

Verb	Subject	Infinitive	Conjugation	Example
can	I	swim	can swim	I can swim across the bay.
could	you	help	could help	You could help with the boxes.
may	she	join	may join	She may join us after lunch.
might	we	need	might need	We might need more paper.
must	they	wait	must wait	They must wait outside the room.
should	he	check	should check	He should check the address again.
would	I	try	would try	I would try the soup with herbs.
will	she	call	will call	She will call after the meeting.

Scramble

Perfect progressive forms combine have been with an -ing verb: have/has been + -ing in the present and had been + -ing in the past. I have been studying for two hours. She has been working all morning. They had been waiting before the train arrived. This structure shows an action that started earlier and continued up to a point in time, or was still in progress before another past event. The perfect part connects the action to a later moment, and the progressive part shows duration and continuation. It often appears in longer verb sequences built from Present Perfect and Present Continuous.

Perfect progressive meaning and use

Usage	Explanation	Example
Action started earlier and continues now	Use have been plus ing form to show an action that began in the past and is still going on now.	I have been studying all afternoon.
Action continued up to a past point	Use had been plus ing form to show an action that was already happening before another past event.	They had been waiting for an hour before the bus came.
Strong focus on duration	Use have been plus ing form when you want to emphasize how long something has lasted.	She has been practicing the piano for years.

Tag questions repeat the auxiliary from the main clause and use the opposite polarity. If the statement is positive, the tag is negative. If the statement is negative, the tag is positive. She is here, isn’t she? They do work there, don’t they? He won’t agree, will he? The auxiliary in the tag matches the tense and form of the main clause: is, do, will, has, did. The subject in the tag is usually a pronoun that refers back to the main clause, such as it, they, she, or you. Tag questions are closely tied to sentence endings and are often used in spoken English, especially alongside Negatives.

Tag question agreement with auxiliaries

Example	Pattern
It is cold, isn't it?	Use the same auxiliary in the tag that appears in the main clause.
They finished early, didn't they?	Match the tense of the main clause in the tag.
She is not late, is she?	Use a positive tag after a negative main clause.
You can come, can't you?	Use a negative tag after a positive main clause.