So and such are used to add emphasis. They both mean “very,” but they are used with different grammatical structures.
1. So → before adjectives and adverbs
Use so before an adjective or an adverb.
- She is so tired.
- He runs so fast.
Structure:
- so + adjective → so tired
- so + adverb → so quickly
2. Such → before nouns (often with adjectives)
Use such before a noun or adjective + noun.
- It’s such a good movie.
- They are such kind people.
Structure:
- such + (a/an) + adjective + noun
3. Key difference
- So → adjective or adverb only
- Such → noun phrase
- She is so intelligent. (adjective)
- She is such an intelligent person. (noun phrase)
4. Common mistakes
- ❌ She is such tired.
- ✔️ She is so tired.
- ❌ It’s so a good idea.
- ✔️ It’s such a good idea.
5. “So” and “Such” with “that”
Both can be used to show a result.
- She was so tired that she fell asleep.
- It was such a long movie that we left early.