Cambridge documents threaten + to-infinitive, while threaten also has object-based constructions such as threatening a person or thing. An -ing form may occur in a larger phrase, but it should not be presented as freely interchangeable with the to-infinitive after threaten.
ReviewedEvidence2 sourcesSectionEnglish Usage
Quick answer
Use “threaten to do” when someone states or signals a possible action; bare “threaten doing” is not a parallel complement for that pattern. An -ing form may occur in a larger phrase, but it should not be presented as freely interchangeable with the to-infinitive after threaten.
Key details
Confusion Familygrammar-and-usage distinction
Rule Familyverb complement pattern
TermsThreaten Doing, Threaten To Do
Further guidance
Boundary
An -ing form may occur in a larger phrase, but it should not be presented as freely interchangeable with the to-infinitive after threaten.
Construction
Cambridge documents threaten + to-infinitive, while threaten also has object-based constructions such as threatening a person or thing.
Decision
Use “threaten to do” when someone states or signals a possible action; bare “threaten doing” is not a parallel complement for that pattern.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
Cambridge documents both admit + -ing and admit to + -ing for acknowledging something. Other passive patterns such as “be admitted to be” are separate constructions.
Both patterns are standard. “Advise waiting” recommends an action generally or in context, while “advise him to wait” names the person who is advised to perform it. A that-clause is another standard option.
When “afford” is followed directly by another verb, standard learner references use a to-infinitive: “afford to do.” An -ing form can appear elsewhere in a sentence, but it is not a like-for-like direct complement after “afford.”
“Agree to do” expresses consent to take an action. An -ing form normally follows a preposition in patterns such as “agree with doing,” which expresses approval rather than the direct promise-to-act construction.
Cambridge documents aim + to-infinitive for intention and aim at for directing effort toward an objective. Do not omit the preposition and present bare “aim doing” as equivalent to “aim to do.”
“Allow” can take an activity as its object, as in “allow smoking,” or a person/thing followed by a to-infinitive, as in “allow visitors to enter.” The patterns answer different structural questions: what is allowed versus who is allowed to do what.
