光 vs 完 (guāng vs wán): Resultative complements of depletion and completion
Both 光 and 完 can act as resultative complements to indicate that something is exhausted or finished. 光 (guāng) stresses that absolutely nothing remains, while 完 (wán) emphasizes that the action has reached its end. They are often interchangeable after verbs like 吃 and 花 when the object is completely depleted, but 完 has a much broader range—it works with any action verb (看, 做, 写) even if nothing is consumed.
光 and 完 are both used as resultative complements to express that an action has reached a final state—typically that something is used up or finished. The key difference lies in the mental emphasis: 光 focuses on total emptiness (nothing left), while 完 focuses on the completion of the action itself. For consumable objects (food, money, water), they are often interchangeable, but 光 carries a stronger, more vivid sense of 'all gone'. However, 完 can be used with a wide variety of verbs (e.g., 做完作业, 看完电影) where 光 is impossible because nothing is being consumed or emptied.
When to use each
Use 光 as a resultative complement after verbs that involve consuming or expending something (吃, 喝, 用, 花) when you want to emphasize that the object is completely exhausted—nothing whatsoever remains. It often conveys a more dramatic sense of emptiness than 完. 光 cannot be used with verbs that do not involve depletion (e.g., 写, 看, 做). For example, you can say 钱花光了, but not 作业写光了.
光 sometimes adds a subtle emotional weight—like 'all gone, nothing left'—that 完 may lack in the same context. It is also less flexible than 完; it only pairs with verbs that can result in a state of depletion.
Use 完 as a resultative complement to indicate that an action is complete or that something is finished. It works with both consumable verbs (吃, 用) and non‑consumable ones (看, 做, 写, 说). When the object is the grammatical subject (e.g., 水喝完了), 完 implies that the object is fully used up, similar to 光. When the agent is the subject (e.g., 我喝完了), the action is finished, but the object may or may not be entirely gone. 完 is the default choice for abstract completion (作业做完了, 电影看完了).
完 is much broader than 光. It is also the only option when you want to say the action is done without referring to depletion (e.g., 我说完了 'I finished speaking'). In consumable contexts, 完 is slightly less emphatic about total emptiness than 光.
At a glance
| 光 | 完 | |
|---|---|---|
| Core meaning | Total depletion: nothing left | Completion of an action (may or may not leave leftover) |
| Verbs it can follow | Only verbs that consume/expend (吃, 喝, 用, 花, 卖, 浪费) | Almost any action verb (吃, 喝, 看, 做, 写, 读, 说, 听) |
| Agent vs object subject | Object subject always means total depletion (钱花光了) | Object subject means total depletion (钱花完了); agent subject means action finished (我花完了, leftover possible) |
| Emotional emphasis | Strong, vivid 'all gone' | Neutral, matter‑of‑fact completion |
| Interchangeability for depletion | Always interchangeable when meaning 'all gone' | Always interchangeable when meaning 'all gone'; also works where 光 cannot |
Examples
- 光他把饮料喝光了。Tā bǎ yǐnliào hē guāng le.He drank all the beverage (nothing left).Emphasizes total emptiness; 喝完了 would also be fine here, but less vivid.
- 完作业做完了，我们去玩吧。Zuòyè zuò wán le, wǒmen qù wán ba.Homework is finished, let's go play.完 is used with a non‑consumable verb. 光 cannot replace 完 here.
- 光钱花光了，不能再买了。Qián huā guāng le, bù néng zài mǎi le.The money is all spent, can't buy any more.Strongly emphasizes that not a cent remains.
- 完水喝完了。Shuǐ hē wán le.The water is finished (completely drunk).Object as subject: 完 here means the water is depleted, just like 光.
- 完我说完了，你有什么意见？Wǒ shuō wán le, nǐ yǒu shénme yìjiàn?I've finished speaking, what's your opinion?完 with an action that has no consumable object; 光 is impossible.
Common mistakes
- Using 光 with verbs that don't involve depletion: e.g., ✗ 作业写光了 (should be 作业写完了). 光 only works with consumable/expendable actions.
- Using 完 with agent subject and assuming the object is always gone: 我吃完了 means 'I finished eating' but could leave food on the plate. To stress total depletion, use 光 or make the object the subject (饭吃得光光的).
- Thinking 完 always means 'nothing left'. In 我看完了那部电影, the movie still exists; it just means the watching action is complete.
- Overusing 光 in abstract contexts: ✗ 问题解决了光了 (sounds odd; use 解决了 or 解决完了).
FAQ
- When do I use 光 vs 完 after 吃, 喝, 用, 花?
- Both are correct and largely interchangeable when the object is completely used up. 光 puts extra emphasis on emptiness—like 'all gone, not a drop left'. 完 is slightly more neutral and also works in contexts where nothing is consumed (e.g., 看完). If you want to be explicit that nothing remains, 光 is a good choice; otherwise 完 is safe.
- Can 完 also mean 'nothing left'?
- Yes—when the consumed object itself is the grammatical subject (e.g., 钱花完了, 饭吃完了), 完 means the object is completely depleted, just like 光. But when the agent is the subject (我花完了), the action is finished but some of the object may remain. 光 never allows that ambiguity: it always implies total depletion regardless of sentence structure.
- I've seen 光 in 我吃光了 and 我吃完了. Are they the same?
- Very similar. 我吃光了 specifically means 'I ate everything (until nothing remains)'. 我吃完了 means 'I finished eating' (the action is complete). In practice, many native speakers use them interchangeably when the context makes depletion clear. However, 我吃完了 could be said even if a little food is left, while 我吃光了 implies the plate is clean.
- Is it wrong to use 光 with 看 or 做?
- Yes. 光 cannot be the complement of 看 (watch/read) or 做 (do) because these actions do not deplete the object. You must use 完: 看完电影 (finish watching the movie), 做完工作 (finish the work). Using 光 in such cases is ungrammatical.