起 vs 了 (qǐ vs liǎo): affordability and feasibility potential complements
起 and 了 are two common potential complements in Chinese, attached to verbs with 得/不 to indicate possibility. 起 (qǐ) primarily expresses affordability—whether one has the financial means or sufficient resources to do something. 了 (liǎo) expresses feasibility, i.e., whether one is able to complete an action given the circumstances. Choosing the right one depends on whether the key constraint is cost/resource (起) or general ability/completion (了).
Both 起 and 了 can serve as potential complements attached to verbs to indicate ability, but they differ in what type of ability is highlighted. 起 (qǐ) focuses on the ability to afford or bear something, often related to money, time, effort, or endurance. 了 (liǎo) focuses on the ability to carry out or complete an action under given circumstances, without necessarily implying resource constraints. The two are not freely interchangeable; using the wrong one can change the meaning or sound unnatural.
When to use each
Use 起 after a verb to indicate that one has the financial means, sufficient resources, or stamina to do something. Common with verbs like 买 (buy), 付 (pay), 经 (withstand), and 承担 (undertake). It often implies a cost or sacrifice that the subject can bear.
起 can also express the ability to withstand or endure something abstract, such as criticism or hardship (e.g., 经得起考验 'can withstand a test').
Use 了 after a verb to indicate that one is able to do something due to external circumstances, personal capacity, or the nature of the task. It often conveys feasibility or the ability to complete an action (e.g., 吃得了 'can finish eating', 去得了 'can manage to go'). It is more general than 起 and does not carry the specific nuance of affordability.
The potential complement 了 is derived from the verb 了 (liǎo) meaning 'to finish' or 'to settle', so it often implies the ability to see something through to completion.
At a glance
| 起 | 了 | |
|---|---|---|
| Core meaning | Affordability / bearing a cost (financial or resource) | Feasibility / ability to complete under circumstances |
| Typical verbs | 买, 付, 经, 承担, 抬 | 吃, 办, 去, 做, 处理 |
| Negative form | V不起 | V不了 |
| Example with 买 | 买得起 = can afford to buy (financial capacity) | 买得了 = can manage to buy (e.g., item is available) |
| Overlap area | Can also be used for non-financial resources (time, energy) | Can be used for general ability; rarely overlaps with 起 |
Examples
- 起这房子太贵了，我买不起。Zhè fángzi tài guì le, wǒ mǎi bù qǐ.This house is too expensive, I can't afford to buy it.Financial inability – 买不起 is the standard negative potential complement for affordability.
- 了这么多菜，你一个人吃得了吗？Zhème duō cài, nǐ yī ge rén chī dé liǎo ma?With so many dishes, can you eat them all (by yourself)?Feasibility: can you finish eating? Not about money.
- 起这么重的箱子，他一个人抬得起吗？Zhème zhòng de xiāngzi, tā yī ge rén tái dé qǐ ma?Can he lift such a heavy box by himself?Physical capacity to bear the weight – 抬得起 uses 起 for endurance.
- 了明天我去不了了，因为还要开会。Míngtiān wǒ qù bù liǎo le, yīnwèi hái yào kāihuì.I can't go tomorrow because I have a meeting.Feasibility: unable to go due to schedule conflict. Note the final 了 is the aspect particle, not the potential complement.
- 起这种材料经得起高温。Zhè zhǒng cáiliào jīng dé qǐ gāowēn.This material can withstand high temperatures.Bearing capacity – 经得起 uses 起 metaphorically for endurance.
- 了这张桌子太矮，我写字写不了。Zhè zhāng zhuōzi tài ǎi, wǒ xiězì xiě bù liǎo.This table is too low; I can't write (properly).Feasibility: unable to perform the action due to the table's height.
Common mistakes
- Using 了 for financial affordability: 我买得了这辆车 should be 我买得起这辆车.
- Using 起 for general ability unrelated to resources: 我吃得起三个汉堡 (incorrect; should be 吃得了) — eating hamburgers is not about affordability.
- Confusing the potential complement 了 with the perfective aspect particle 了 (le). They are distinct in pronunciation and function.
- Using 起 with verbs that don't imply cost or burden, e.g., 读得起书 means 'can afford to study', but if you mean 'can read the book', use 读得了.
FAQ
- When do I use 起 vs 了 as a potential complement?
- Use 起 when the key question is whether you can afford or bear something in terms of money, effort, or endurance. Use 了 when the question is whether you are able to do something given the circumstances, regardless of cost. For example, 买得起 means 'can afford to buy', while 买得了 means 'can manage to buy' (e.g., it's still available or you have time).
- Can I use 得了 to talk about financial ability?
- No, 得了 does not imply financial ability. If you say 我买得了, it means you are able to buy it (maybe it's available), not that you have enough money. To express affordability, use 得起.
- What are the negative forms of these complements?
- The negative forms are V不起 and V不了. For example, 买不起 (can't afford), 吃不了 (can't finish eating).
- Is it possible to use both with the same verb?
- Yes, some verbs can take both, but the meaning differs. For instance, 承担得起 means 'can afford to bear' (e.g., financial liability), while 承担得了 means 'can manage to undertake' (e.g., the task). Choosing depends on the type of ability you want to highlight.