Zero Infinitive / Bare Infinitive: Rules, Examples and Exercises
ENGLISH MINES™ | PAUL ACADEMY • Grammar made clear
Bare infinitive rules can be easy to remember once you recognise the patterns. This complete lesson explains zero infinitives with examples, active–passive changes, common errors and 25 questions with explanatory answers.
In This Lesson
What Is a Zero Infinitive or Bare Infinitive?
A bare infinitive is the base form of a verb used without the infinitive marker ‘to’: go, write, speak, be and have. It is also called the zero infinitive. Compare ‘She wants to learn’ with ‘She can learn’. Both contain an infinitive, but only the first has ‘to’. Knowing which expression comes before the verb helps you choose the correct form.
Quick answer: use a bare infinitive after core modal verbs, active make/let/have causatives, certain perception verbs, and expressions such as had better and would rather. Some patterns change in the passive voice.
Finite verbs and non-finite verbs
A finite verb anchors a clause in tense or modality and may show agreement: ‘She writes’; ‘They write’; ‘She wrote’. A non-finite form does not independently mark tense or subject agreement. In ‘She can write’, can is finite and write is a bare infinitive. In ‘She wants to write’, wants is finite and to write is a to-infinitive.
The base form is a shape; ‘bare infinitive’ describes its grammatical use. In ‘They play daily’, play is a finite present-tense verb. In ‘They can play’, play is a bare infinitive. Do not label every verb without ‘to’ an infinitive.
Bare Infinitive vs To-Infinitive, Gerund and Participle
Form | Example and function |
|---|---|
Bare infinitive: learn | She can learn quickly. Follows a modal. |
To-infinitive: to learn | She hopes to learn quickly. Follows hope. |
Gerund: learning | Learning takes practice. The -ing clause functions as subject. |
Present participle: learning | She is learning. Used with is in the progressive verb phrase. |
An -ing ending alone does not tell you the function. Compare ‘Swimming is enjoyable’ with ‘The children are swimming’. Similarly, be can be a bare infinitive: ‘You must be careful’. In ‘She may have forgotten’, have is the bare infinitive after may.
Seven Core Bare Infinitive Rules with Examples
1. After core modal verbs
Use modal + base verb after can, could, may, might, must, shall, should, will and would. Do not insert ‘to’, add -s for a singular subject, or use the past form simply because the modal refers to the past.
She can speak four languages. NOT: She can to speak / can speaks.
You must submit the assignment before noon.
They should leave early. He could swim when he was six.
We ought to respect others; she used to live here. Ought to and used to retain ‘to’. Have to also retains it.
2. After modal need and dare
When need and dare act as modal auxiliaries, they take a bare infinitive: ‘You need not attend’; ‘Dare he interrupt?’; ‘How dare you open my letter?’ Modal uses occur especially in negatives and questions.
As an ordinary main verb, need takes a to-infinitive: ‘He does not need to attend’. Dare is more flexible when it means ‘be brave enough’: ‘She does not dare (to) disagree’ allows either form. When dare means ‘challenge someone’, use object + to-infinitive: ‘I dare you to try’. Do not apply need’s pattern mechanically to every use of dare.
3. After active make, let and have
Use subject + make/let/have + object + bare infinitive when these verbs express causing, permitting or arranging an action.
Make: The teacher made the students rewrite the answer.
Let: Her parents let her attend the concert.
Have: I will have my assistant call you.
Contrast: Her parents allowed her to attend. The rain forced us to stay indoors. Allow, force, ask and tell do not follow the same pattern as make.
Also distinguish ‘have someone do something’ from ‘have something done’: ‘I had the mechanic check the brakes’ names the person doing the work; ‘I had the brakes checked’ focuses on the service performed.
4. After active verbs of perception
See, hear, watch, notice and feel can take object + bare infinitive: ‘I saw her cross the road’; ‘We heard him sing’; ‘They watched the plane land’. This construction presents the action as a whole event.
Object + -ing presents an action in progress: ‘I saw her crossing the road’. The distinction is a viewpoint, not a guarantee that every real-life detail was observed. ‘We listened to the soloist perform’ is also grammatical in the active voice; avoid forcing it into an unnatural word-for-word passive.
5. After had better, would rather and would sooner
For advice, use had better + bare infinitive: ‘You had better revise today’. Its negative is ‘You had better not delay’. Although it contains had, this expression normally gives advice about the present or future.
For preference with the same subject, use would rather + bare infinitive: ‘I would rather walk than wait’; ‘He would sooner apologise than argue’. Keep the two verbs parallel.
Different subjects require a different pattern: ‘I would rather you stayed here’ uses a past-form clause for a present/future preference. Also, ‘rather than’ does not always demand a bare infinitive: it can connect nouns or -ing forms, as in ‘reading rather than watching television’.
6. After do nothing but / except
In patterns such as do/does/did nothing but or except, the following verb is normally bare: ‘They did nothing but complain’; ‘The dog does nothing except bark’. Compare ‘He had no choice but to obey’, where the preceding construction requires to obey.
The relevant structure matters, not merely the presence of the word do somewhere earlier. ‘All I did was (to) ask a question’ permits both ask and to ask. Do not turn the useful ‘nothing but’ pattern into a universal rule about every occurrence of but, except or than.
7. After Why / Why not in suggestions
Use Why + bare infinitive to question a proposed action: ‘Why waste time?’ Use Why not + bare infinitive to suggest one: ‘Why not consult an expert?’ Contrast the ordinary finite question ‘Why do you waste time?’ Do not write ‘Why to waste time?’ in this suggestion pattern.
Bare Infinitives in Active and Passive Voice
With make, see and hear in the patterns below, the active bare infinitive becomes a to-infinitive in the passive. Preserve the original participants and tense.
Active voice | Passive voice |
|---|---|
The teacher made Riya rewrite it. | Riya was made to rewrite it by the teacher. |
We saw him enter the room. | He was seen to enter the room. |
They heard her sing. | She was heard to sing. |
The guard let Arjun enter. | Arjun was allowed to enter by the guard. |
For permission, be allowed to is the natural passive equivalent of let someone do something. Limited expressions such as ‘He was let go’ exist, but they are not a general passive template for every use of let. Causative have is normally rephrased rather than changed into ‘was had to’.
Do not generalise the make/see/hear passive pattern to every perception verb. Instead of the awkward ‘The soloist was listened to to perform’, write a natural sentence such as ‘The soloist was heard to perform the entire concerto’. This changes the reporting verb, so a transformation exercise should state that change explicitly.
Special Patterns: Help, Cannot Help and Bid
Help somebody do / to do
In the active voice, both forms are standard: ‘She helped me pack’ and ‘She helped me to pack’. For formal school writing in the passive, use ‘I was helped to pack’. This is a dependable model for learners.
Cannot help doing / cannot help but do
‘I cannot help laughing’ takes an -ing form. ‘I cannot help but laugh’ takes a bare infinitive. Both mean that the reaction is difficult to prevent. Do not mix them into ‘cannot help but laughing’.
Bid / bade / bidden: a literary pattern
In the sense ‘command’, bid can take object + bare infinitive: ‘The officer bade the men halt’. A literary passive is ‘The men were bidden to halt’. For everyday writing, ‘ordered the men to halt’ is clearer. Keep this advanced use separate from the meaning ‘offer a price’.
Common Bare Infinitive Mistakes
Avoid | Use instead |
|---|---|
She can to sing. | She can sing. |
The teacher made us to write. | The teacher made us write. |
You had better to leave. | You had better leave. |
He was seen enter. | He was seen to enter. |
You need not to worry. | You need not worry. |
I would rather to walk. | I would rather walk. |
Why not to try again? | Why not try again? |
They forced us wait. | They forced us to wait. |
Bare Infinitive Exercises: 25 Questions
Try the questions before reading the explanations. This practice is adapted from the uploaded master guide; unclear prompts have been revised. It supports school grammar revision without claiming to reproduce an official board paper.
Part A — Correct the error (1–10)
1. You had better to finish your homework before watching television.
2. The teacher made all the students to write the explanation again.
3. She does nothing all day except to watch television.
4. We heard the singer to perform her final song.
5. How dare you to enter my office without permission?
6. I would rather to study literature than to pursue economics.
7. He was seen enter the warehouse last night.
8. Why to spend so much money on an unnecessary luxury?
9. You need not to worry about the results.
10. The manager had his secretary to type the memo.
Part B — Transform as directed (11–20)
11. The magistrate made the culprit confess his crime. (Change into the passive.)
12. People saw him escape through the back door. (Change into the passive.)
13. You should leave now. (Rewrite using ‘had better’.)
14. I prefer dying to begging. (Rewrite using ‘would rather … than’.)
15. She was made to clean the laboratory by the supervisor. (Change into the active; retain ‘she’ as ‘her’.)
16. We heard the soloist perform the entire concerto. (Change into the passive.)
17. You are not required to pay any extra fees. (Rewrite using ‘need not’.)
18. The officer commanded the men to halt. (Replace ‘commanded’ with ‘bade’.)
19. It is unnecessary to hire a private guide. (Begin with ‘Why’.)
20. My parents allowed me to study abroad. (Rewrite using ‘let’.)
Part C — Supply the correct form (21–25)
21. The heavy rain forced us ___ indoors. (stay)
22. They did nothing but ___ about the service. (complain)
23. The suspects were observed ___ the bank. (leave)
24. You had better ___ your vehicle. (lock)
25. I cannot help but ___ sorry for him. (feel)
Answers with Grammatical Explanations
Compare the governing pattern in each answer with your own sentence. The explanation is as important as the missing word.
1. You had better finish your homework before watching television.
Explanation: Had better takes the bare infinitive finish.
2. The teacher made all the students write the explanation again.
Explanation: Active make + object takes write without to.
3. She does nothing all day except watch television.
Explanation: Does nothing except is followed here by bare watch.
4. We heard the singer perform her final song.
Explanation: Active hear + object takes a bare infinitive for a whole-event reading.
5. How dare you enter my office without permission?
Explanation: How dare you takes enter without to.
6. I would rather study literature than pursue economics.
Explanation: Would rather … than links parallel bare infinitives.
7. He was seen to enter the warehouse last night.
Explanation: The passive was seen takes a to-infinitive in this pattern.
8. Why spend so much money on an unnecessary luxury?
Explanation: Why + bare infinitive questions the usefulness of the action.
9. You need not worry about the results.
Explanation: Modal need not takes worry, not to worry.
10. The manager had his secretary type the memo.
Explanation: Active causative have + person takes a bare infinitive.
11. The culprit was made to confess his crime by the magistrate.
Explanation: Passive made restores to before confess.
12. He was seen to escape through the back door.
Explanation: Passive perception uses to escape; the vague agent people may be omitted.
13. You had better leave now.
Explanation: Had better takes leave. It gives stronger advice than should, so the force is slightly stronger.
14. I would rather die than beg.
Explanation: Would rather takes die and the parallel comparison takes beg.
15. The supervisor made her clean the laboratory.
Explanation: The active restores the supervisor as subject; her preserves the original person.
16. The soloist was heard to perform the entire concerto.
Explanation: Passive heard takes to perform. This revised question uses heard, avoiding an unnatural passive of listened to.
17. You need not pay any extra fees.
Explanation: Modal need not expresses absence of necessity and takes pay.
18. The officer bade the men halt.
Explanation: Bade, meaning commanded, takes object + bare infinitive. This is literary usage.
19. Why hire a private guide?
Explanation: Why + hire challenges the need for the action.
20. My parents let me study abroad.
Explanation: Let + object takes study without to.
21. to stay
Explanation: Force + object requires a to-infinitive.
22. complain
Explanation: Did nothing but takes a bare infinitive in this construction.
23. to leave
Explanation: Passive were observed takes a to-infinitive in this reporting pattern.
24. lock
Explanation: Had better takes the bare infinitive.
25. feel
Explanation: Cannot help but takes a bare infinitive; compare cannot help feeling.
Frequently Asked Questions
Are zero infinitive and bare infinitive the same?
Yes. Both names refer to an infinitive without the marker to: ‘She can dance’. Bare describes the unmarked form; zero refers to the absence of to.
What is the difference between a bare infinitive and a full infinitive?
A full or to-infinitive includes to, as in to read. A bare infinitive omits it, as in ‘You must read’. The preceding verb or expression determines the choice.
Can we use a bare infinitive after help?
Yes, in the active voice: ‘They helped us understand’ and ‘They helped us to understand’ are both correct. Use ‘We were helped to understand’ as the formal passive model.
Is ‘to’ always an infinitive marker?
No. In ‘I look forward to meeting you’, to is a preposition followed by an -ing form. Compare ‘I hope to meet you’, where to introduces an infinitive.
Does every passive sentence need a to-infinitive?
No. ‘The work must be finished’ contains bare be after must. The to-infinitive shift discussed above belongs to particular patterns such as ‘was made to work’ and ‘was seen to enter’.
Ready Reckoner: Revise in One Minute
Core modal + bare verb: can go, must work, should be.
Active make/let/have + object + bare verb: made me wait.
Perception + object + bare verb: saw her cross; -ing highlights progress.
Had better / would rather + bare verb: better leave; rather stay.
Modal need not / dare not + bare verb: need not worry.
Do nothing but/except + bare verb: did nothing but complain.
Why not + bare verb: Why not try?
Active help accepts either form; formal passive: was helped to learn.
Passive make/see/hear: was made/seen/heard to do.
Always check the whole structure, not just one nearby word.
Continue Learning on English Mines
Gerund or Infinitive: Rules, Examples & Exercises — compare verb patterns and practise choosing the correct form.
Active vs Passive Voice: Master the Rules & Examples — revise voice changes before tackling infinitive transformations.
Prefer and Would Rather: Rules and Examples — strengthen your understanding of preference structures.
Mastering the Usage of Rather: Rules, Examples & Quiz — explore related uses of rather with extra practice.
Prepositions & Modals: Grammar Quiz — test modal patterns and distinguish prepositional to from infinitival to.
Going To in English Grammar: Rules, Examples and Practice — compare be going to + verb with modal + bare infinitive.
Further Reading
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