Practice
Infinitives in English: a practical introduction
Sign in to saveI want to leave before dark, but I can stay for another hour. Leave and stay are both infinitive forms, but only the first one has to.
Recognize a to-infinitive and a bare infinitive, then choose the form that fits common English verb patterns.
Read and practice
Read the examples and try the written questions in this guide. Listening recordings are not available for this lesson yet.
Try the written questions
I want to learn more. /aɪ wɒnt tə lɜːn mɔː/
The short answer
Use a to-infinitive after many verbs, such as want, decide, and hope. Use a bare infinitive after modal verbs such as can, should, and must. Check whether to is an infinitive marker or a preposition before you choose the next form.
Nadia wants to borrow the charger.
Why it works: Wants is followed by to plus the base verb borrow.
4 more examples
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We decided to meet after work.
Decided is followed by to plus the base form meet.
Not this:We suggested
meetingafter work. What changes: Suggest has a different pattern here and is followed by an -ing form. -
Leo can carry the boxes.
Can is followed by the base form carry without to.
Not this:Leo hopes
to carrythe boxes. What changes: Hopes normally takes a to-infinitive in this meaning. -
I look forward to meeting the team.
Here to is a preposition, so it is followed by the -ing form meeting.
Not this:I hope
to meetthe team. What changes: Hope is followed by a to-infinitive, so meet stays in the base form. -
The guests were pleased to be invited.
This is a passive to-infinitive: to be plus a past participle.
Not this:The guests seem
to have arrivedearly. What changes: This perfect infinitive shows an action that happened before the seeming.
Read the full guide
Start with the word before the verb. Want usually needs to plus a base verb, so write want to leave. Can takes a base verb without to, so write can leave. This check is more reliable than looking at the verb alone.
Find the base form of the verb
An infinitive uses a verb's base form, such as go, read, or finish. The form does not carry the tense by itself. Another word in the verb group can show time, person, or possibility.
They plan to travel in July.
Travel is the base form. Plan changes to plans or planned when the sentence needs a different tense or subject.
What is the base verb in to finish?
The base verb is finish. To is the marker in a to-infinitive.
Use to after many ordinary verbs
Many common verbs are followed by to plus a base verb. Want, need, decide, plan, and hope are useful patterns to learn. The first verb carries the tense; the infinitive completes its meaning.
I need to send the invoice today.
Need is the main verb. To send tells us what the speaker needs to do.
Priya decided to take the later bus.
Decided is in the past tense, while take remains in the base form after to.
Use a bare infinitive after a modal
Modal verbs include can, could, may, might, should, will, and must. A modal is followed directly by a base verb. Do not add to between the modal and that verb.
You should check the address first.
Should shows advice. Check is the bare infinitive after the modal.
Which form follows must: to wear or wear?
Use wear: You must wear a helmet.
Check whether to is a preposition
To is not always an infinitive marker. It can be a preposition before a noun, pronoun, or -ing form. The phrase look forward to is followed by an -ing form, even though it contains to.
She is used to working from home.
To belongs to the phrase is used to. Working is an -ing form, not a to-infinitive.
What follows look forward to in I look forward to hearing from you?
Use an -ing form: hearing. In this phrase, to is a preposition.
Use an infinitive to give a purpose
A to-infinitive can explain why someone does something. This use often answers the question why? It usually comes after the action it explains.
Rosa called the hotel to confirm the booking.
To confirm gives Rosa's purpose for calling the hotel.
He saved the document to review it later.
The infinitive explains the reason for saving the document.
Recognize longer infinitive patterns
An infinitive can contain more than one word. Use to be plus a past participle for a passive infinitive, and to have plus a past participle for a perfect infinitive. The base forms after to are still be and have.
Everyone expects the results to be published soon.
To be published is passive because the results receive the action.
She seems to have forgotten the appointment.
To have forgotten places the forgetting before the present impression.
Before you go
Remember this
Find the word before the verb. Many ordinary verbs need to plus a base form, while modal verbs take a bare infinitive. When you see to, decide whether it is an infinitive marker or a preposition before choosing the next word.
Practice with the written examples
You can practice with the written questions in the Learn tab. Each answer includes an explanation.
Try the written questionsListening test not available yet
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Try the written questionsQuestions about "Infinitives in English: a practical introduction"
What is an infinitive in English?
An infinitive uses a verb's base form without showing tense or a subject by itself. A to-infinitive has to plus that base form, as in Nadia wants to borrow the charger. A bare infinitive uses the base form alone, as in Nadia can borrow the charger.
Nadia wants to borrow the charger.
Which verbs are followed by a to-infinitive?
Many common verbs are followed by to plus a base verb, including want, need, decide, plan, and hope. For example, We decided to meet after work. Learn a new verb together with a complete sentence so that you remember its pattern.
Nadia can borrow the charger.
Why does can not use to before the next verb?
Can is a modal verb. Modal verbs take a bare infinitive directly after them, so Leo can carry the boxes is correct. The base form carry follows can without to. The same pattern works with should, might, and must.
We decided to meet after work.
Is to always part of an infinitive?
No. To can be a preposition. In I look forward to meeting the team, to belongs to the phrase look forward to and meeting is an -ing form. Compare this with I hope to meet the team, where to begins a to-infinitive.
We suggested meeting after work.
What are passive and perfect infinitives?
A passive infinitive uses to be plus a past participle, as in The guests were pleased to be invited. A perfect infinitive uses to have plus a past participle, as in The guests seem to have arrived early. These longer forms still begin with the base verbs be or have.
Leo can carry the boxes.