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to do -- Infinitive

Grammar forms of the infinitive#

FormStructureExample
Simple (Active)to + Vto do
Simple (Passive)to be + V-edto be done
Continuous (Active)to be + V-ingto be doing
Perfect (Active)to have + V-edto have done
Perfect (Passive)to have been + V-edto have been done

Syntactic functions of the infinitive#

Syntactic FunctionExplanation & Example
SubjectOften, it is used as a placeholder and refers to the subject.
• To master a language requires patience.
• It requires patience to master a language.
ObjectThe infinitive follows and is the object of a transitive verb.
• She hopes to succeed.
• We have arranged to meet them.
Subject Complement (Predicative)The infinitive follows a linking verb (most commonly be) and renames or describes the subject.
• His ultimate goal is to innovate.
• The company’s strategy was to expand rapidly.
Object ComplementThe infinitive follows a direct object and completes its meaning. Common with verbs of persuasion, causation, or perception.
• The manager encouraged her to apply.
• They appointed him to lead the project.
Adjective ComplementThe infinitive follows an adjective to complete its meaning, often explaining the cause of the state described.
• I am delighted to be here.
• This problem is difficult to solve.
AdverbialThe infinitive phrase modifies a verb, an adjective, or an entire clause to express purpose, reason, or result.
• Purpose: He works hard to support his family.
• Result: She grew up to be a brilliant leader.
Attribute (Post-modifier)The infinitive functions as an adjective phrase that post-modifies a noun or pronoun. It often implies a future action or necessity.
• She was the first to arrive.
• Is there anything to eat?
Independent Element (Disjunct)The infinitive phrase is used as a sentence modifier or disjunct, expressing the speaker’s comment or attitude on the sentence.
• To be frank, this plan is flawed.
• To put it simply, we need more data.

Interrogative + to#

Function as noun phrase.

  • We don’t know what to do next. (object)
  • The challenge is how to proceed. (predicate)
  • It is not yet certain how to do it. (subject)

Bare infinitive(infinitive without to)#

Used after

  • Perception verbs: see,hear,watch…
  • Causative verbs: make,let,have..
  • Modal verbs: can,will,must…
to do -- Infinitive
https://fishlet.top/posts/to-do----infinitive/
Author
Ember
Published at
2025-11-22
License
CC BY-NC-SA 4.0