可以 (kěyǐ) - Can/May (Permission)

Use three checks whenever you apply 可以: structure, function, and register. Structure tells you where the pattern attaches. Function tells you what meaning or nuance it contributes (time, contrast, cause, condition, emphasis, intention, etc.). Register tells you whether the line sounds conversational, neutral, or formal. Most learner mistakes happen when one of these checks is ignored.

Natural output also depends on rhythm. Short, balanced clauses usually sound better than literal word-for-word translation. Start with compact frames, then expand sentence length while preserving agreement and tone consistency.

1. 1Core clause + 可以 + continuation
2. 2Question and negative variants of the same frame
3. 3Contrast/condition extension for multi-clause sentences

• Use it in daily conversation for clear and natural expression.
• Use it in writing when you need cohesive sentence flow.
• Use it in exam tasks to demonstrate grammar control and nuance.
• Use it when switching intentionally between neutral, polite, and formal style.
• Use it first with high-frequency vocabulary, then expand to abstract contexts.

• Do not overuse one pattern repeatedly across consecutive sentences.
• Do not mix incompatible registers inside one short statement.
• Do not rely on direct translation if target-language order differs.
• Do not force this pattern where a simpler form is more natural.

1. 1Correct marker inside an incorrect sentence frame.
2. 2Grammatically possible but collocationally unnatural combinations.
3. 3Losing agreement/consistency in longer clauses.
4. 4Applying one memorized translation to every context.

可以 can overlap with nearby structures, but pragmatic tone often differs: directness, softness, certainty, or formality. Compare minimal pairs in real context rather than relying only on dictionary glosses. Context-first comparison is the fastest route to natural usage.