To-Infinitives: Form, Meaning and Complementation
Use simple, continuous, perfect, passive, split, and bare infinitives within verb, adjective, noun, and purpose constructions.
Learning Objective
To-Infinitives: Form, Meaning and Complementation
Choose an infinitive form and complement pattern that expresses the intended subject, time, aspect, voice, and purpose.
Clear Explanation
The infinitive has no finite tense but can express relative time, aspect, and voice through to do, to be doing, to have done, and passive variants. The governing word determines whether to, a bare infinitive, or an -ing form is licensed.
Form and Structure
to + base; to be + -ing; to have + past participle; to be/to have been + past participle
“She appears to understand the risk.”
Splitting an infinitive is grammatical and can prevent ambiguity or improve rhythm. Judge placement by clarity and style, not by a blanket prohibition.
Meaning and Use
Relative time
A perfect infinitive places its event before the time of the governing verb; a continuous infinitive foregrounds an unfolding process.
“He claims to have warned them.”
Understood subjects
For + noun phrase can introduce an infinitive subject, while control verbs assign the understood subject through their syntax.
“It is important for everyone to respond.”
To or bare form
Modals and certain causative or perception patterns take a bare infinitive; passive versions may restore to.
“They made him leave; he was made to leave.”
Common Errors and Meaning Traps
She seems to understood the problem.
She seems to understand the problem.
A simple infinitive uses the base form after to.
He claims to finish it yesterday.
He claims to have finished it yesterday.
Use a perfect infinitive for an event earlier than the present claim.
They made us to wait.
They made us wait.
Active causative make takes object + bare infinitive.
Guided Practice
Use the grammar in context
“They seem to be waiting outside.”
“The files are believed to have been deleted.”
Build a set of related sentences using simple, continuous, perfect, passive, and perfect-passive infinitives, then identify each understood subject.
Quick Recap
The infinitive has no finite tense but can express relative time, aspect, and voice through to do, to be doing, to have done, and passive variants. The governing word determines whether to, a bare infinitive, or an -ing form is licensed.
A perfect infinitive places its event before the time of the governing verb; a continuous infinitive foregrounds an unfolding process.
Splitting an infinitive is grammatical and can prevent ambiguity or improve rhythm. Judge placement by clarity and style, not by a blanket prohibition.
A simple infinitive uses the base form after to.
Independent Mastery Check
Complete these four checks before taking the quiz. If one feels difficult, return to the matching section and try again.
Explain the core rule in your own words without looking back at the lesson.
Find the target form in “She appears to understand the risk.” and explain what it communicates in this context.
Explain why “She seems to understand the problem.” is the recommended revision for “She seems to understood the problem.”.
Build a set of related sentences using simple, continuous, perfect, passive, and perfect-passive infinitives, then identify each understood subject.
Continue at C1-C2 Level
Aim for at least 5 out of 6 in the quiz below. For every missed answer, read the explanation, return to the relevant section, and try the quiz again.
Which statement best explains To-Infinitives: Form, Meaning and Complementation?
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