Be Sad To Do vs. Sad About Something distinguishes two directly documented complement patterns for the adjective “sad.” Use sad + to-infinitive for the directly documented infinitival construction; use sad about + noun phrase for the separately documented prepositional construction. The page stays within those attested patterns and does not infer a broader rule from synonymy.
ReviewedEvidence1 sourceSectionEnglish Usage
Quick answer
Use sad + to-infinitive when the adjective takes its documented infinitive complement; use sad about + noun phrase when the complement is introduced by the documented preposition.
Key details
Confusion Familyadjective-complement
Rule Familyadjective complementation
Termssad + to-infinitive, sad about + noun phrase
Choose the right form
Decision table for Be Sad To Do vs. Sad About Something
Meaning / situation
Construction
Decision
sadness linked to an event or action expressed as an infinitive
sad + to-infinitive
use the documented infinitive pattern
sadness about a named matter, event, or situation
sad about + noun phrase
use “about” to name the matter
Quick tests
Event-or-matter test
Are you presenting the sad event through an infinitive, or naming the matter that causes the sadness?
If yes: Use “sad to + verb.”
If no: Use “sad about + noun phrase.”
Caveat: The comparison covers the reviewed complement patterns and does not declare every other possible complement impossible.
Examples
Example
I was sad to hear that the shop had closed.
The infinitive presents the event associated with sadness.
Example
They were sad about the cancellation.
“About” introduces the matter causing sadness.
Example
She was sad to leave and sad about the timing.
The sentence shows the two complement relationships side by side.
Further guidance
Core difference
Use sad + to-infinitive for the directly documented infinitival construction; use sad about + noun phrase for the separately documented prepositional construction.
Style Boundary
Treat this as a comparison of directly documented complement patterns, not as a claim that every other complement is impossible. Choose the construction that matches the intended grammatical relationship.
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.
Be Afraid To Do vs. Afraid Of Something distinguishes two directly documented complement patterns for the adjective “afraid.” Use afraid + to-infinitive for the directly documented infinitival construction; use afraid of + noun phrase for the separately documented prepositional construction. The page stays within those attested patterns and does not infer a broader rule from synonymy.
Be Alarmed To Do vs. Alarmed At Something distinguishes two directly documented complement patterns for the adjective “alarmed.” Use alarmed + to-infinitive for the directly documented infinitival construction; use alarmed at + noun phrase for the separately documented prepositional construction. The page stays within those attested patterns and does not infer a broader rule from synonymy.
Be Amused To Do vs. Amused By Something distinguishes two directly documented complement patterns for the adjective “amused.” Use amused + to-infinitive for the directly documented infinitival construction; use amused by + noun phrase for the separately documented prepositional construction. The guide stays within those attested patterns and does not infer a broader rule from synonymy.
Be Annoyed To Do vs. Annoyed About Something distinguishes two directly documented complement patterns for the adjective “annoyed.” Use annoyed + to-infinitive for the directly documented infinitival construction; use annoyed about + noun phrase for the separately documented prepositional construction. The page stays within those attested patterns and does not infer a broader rule from synonymy.
Be Astonished To Do vs. Astonished At Something distinguishes two directly documented complement patterns for the adjective “astonished.” Use astonished + to-infinitive for the directly documented infinitival construction; use astonished at + noun phrase for the separately documented prepositional construction. The page stays within those attested patterns and does not infer a broader rule from synonymy.
Be Astounded To Do vs. Astounded By Something distinguishes two directly documented complement patterns for the adjective “astounded.” Use astounded + to-infinitive for the directly documented infinitival construction; use astounded at/by + noun phrase for the separately documented prepositional construction. The guide stays within those attested patterns and does not infer a broader rule from synonymy.
