可 — Bare 可 set straight before a verb in written register: doing the fronted thing serves to bring about the good outcome; the compressed, formal form of 可以.

TSUMUGU · TBCL 4 (est.) · 語法

可 grammar point · tier 1 · 可 — written-register 'can / serves to': bare 可 before a verb, an activity enables a good outcome

· kě

Bare 可 set straight before a verb in written register: doing the fronted thing serves to bring about the good outcome; the compressed, formal form of 可以.

Hook inherited from 可以.

Bare 可 set straight before a verb in written register

框 · Frame

[activity / condition] 可 [verb phrase naming the benefit]

觸 · Trigger

Writing formally, you name a thing done and the good it serves to bring about, and want the tight one-syllable 'can' instead of 可以.

序 · The move

1front the activity or condition that does the workis the subject a thing done, not a person being granted leave?

2set bare 可 straight before the verb, no 以is the register written / formal? in speech 可以 is the natural choice

3name the good outcome the activity reachescould 可以 swap in unchanged here? if so the enabling reading is the live one

例 · Examples

1做好do well資源回收resource recycling可can / serves to改善improve環境the environment。

Doing resource recycling well can improve the environment.

界 · Boundary

可以3

Same enabling-benefit reading; register sorts them. 可3 is bare and written (可改善環境), the yes laid straight on the verb; 可以3 carries 以 and runs in speech (可以讓身體健康). Formal text takes 可; everyday talk takes 可以.

能

可3 frames the activity as good for the result — doing it serves to reach the outcome; 能 says the conditions make a thing possible at all. They overlap, but 可3 carries the benefit, 能 carries bare possibility.

padding it back to speech register in formal text: 做好資源回收可以改善環境（natural in talk, loose on the page） → 做好資源回收可改善環境

fronting a person granted leave: 你可改善環境 → 做好資源回收可改善環境（可3 takes an activity as subject, not a permitted person）

negating with 沒: 沒可改善環境 → 不可改善環境

English 'can' is one word for ability, permission, and 'it serves to do good' alike, and carries no register split, so learners miss that Mandarin's bare 可 is the written-formal twin of spoken 可以 and reach for 可以 on the page.