Potential Complements: 能, 会, 可以, 得, and 不得 Compared

Core examples: 看得懂, 听不清楚, 买得到, 做不完, 进不去, 不得入内, 会游泳, 可以走. Recommended feature module: Before/after translation traps table. Show English “can” split into several Mandarin structures. Related internal articles: 066, 071, 072, 074, 086, 093, 095.

English “can” is too blunt for Mandarin

English uses “can” for many different meanings:

I can swim.
Can I go in?
I can understand it.
I can finish it today.
You can buy it online.
You can’t enter.

Mandarin divides these meanings across several structures:

The most Mandarin-specific structure is the potential complement:

Verb + 得 + Complement = can achieve the result
Verb + 不 + Complement = cannot achieve the result

Examples:

看得懂 / 看不懂
can understand by reading / cannot understand by reading

听得清楚 / 听不清楚
can hear clearly / cannot hear clearly

买得到 / 买不到
can obtain by buying / cannot obtain

做得完 / 做不完
can finish doing / cannot finish doing

进得去 / 进不去
can get in / cannot get in

Potential complements are not just another way to say 能. They locate possibility inside a specific verb-result path.

1. Review: result and direction complements become potential

From article 071:

听懂 = understand by listening
写完 = finish writing
找到 = find
买到 = obtain by buying

Potential versions:

听得懂 / 听不懂
can / cannot understand by listening

写得完 / 写不完
can / cannot finish writing

找得到 / 找不到
can / cannot find

买得到 / 买不到
can / cannot get/buy

From article 072:

进去 = go in
出来 = come out / emerge
看出来 = discern
想起来 = remember

Potential versions:

进得去 / 进不去
can / cannot get in

出得来 / 出不来
can / cannot get out/come out

看得出来 / 看不出来
can / cannot tell by looking

想得起来 / 想不起来
can / cannot remember

The structure tests whether the result or directional endpoint is achievable.

2. 能 vs potential complement

Both can express ability, but they are not identical.

我能看懂这篇文章。
Wǒ néng kàn dǒng zhè piān wénzhāng.
I can understand this article.

我看得懂这篇文章。
Wǒ kàn de dǒng zhè piān wénzhāng.
I can understand this article by reading it.

The difference is often subtle. A practical learner distinction:

Compare:

我今天能做完。
I can finish it today.  (conditions/time/ability allow it)

我今天做得完。
I can get it finished today.  (the task is finishable by doing)

In many cases both are acceptable, but the potential complement feels more integrated and result-specific.

3. 会: learned skill or likelihood

会 often marks learned skill:

我会游泳。
Wǒ huì yóuyǒng.
I can swim.

她会开车。
Tā huì kāichē.
She can drive.

Do not use 会 for every “can.”

我会看懂这篇文章。  possible only in a future/likelihood sense: I will be able to / I’ll understand it.
我看得懂这篇文章。  natural for “I can understand this article.”

会 can also mean “will / likely to”:

明天会下雨。
Míngtiān huì xià yǔ.
It will probably rain tomorrow.

So 会 is not simply ability. It has learned-skill and likelihood uses.

4. 可以: permission and acceptability

可以 often answers whether something is allowed, acceptable, or possible under rules/social conditions.

我可以进去吗？
Wǒ kěyǐ jìnqù ma?
May I go in?

这里可以停车。
Zhèlǐ kěyǐ tíngchē.
You can park here.

现在可以走了。
Xiànzài kěyǐ zǒu le.
We can go now.

Compare:

我进得去。
I can get in.  (physically/technically able to enter)

我可以进去。
I may enter / I’m allowed to enter.

If the door is too narrow, use 进不去. If the guard says no, use 不可以进去 or a formal prohibition.

5. 不得: formal prohibition and fixed potential-like forms

不得 appears in two different zones.

Formal prohibition

非工作人员不得入内。
Fēi gōngzuò rényuán bùdé rùnèi.
Non-staff may not enter.

未经许可，不得转载。
Wèijīng xǔkě, bùdé zhuǎnzǎi.
May not be reproduced without permission.

This 不得 is formal/legal/institutional. It does not sound like ordinary casual 不能.

Potential complement pattern with 得/不

In forms like 看得懂 / 看不懂, the 得 is not the same as formal 不得. The negative inserts 不 between verb and complement.

看得懂  ✓
看不懂  ✓
看不得懂 ✗ for standard potential complement

Keep these separate in your notes.

6. Common potential complements

These are worth learning as phrase patterns, not one-off grammar curiosities.

7. Translation traps with “can”

The best question is not “How do I say can?” It is:

What kind of can is this?
skill, permission, condition, result-achievement, or formal prohibition?

8. Practice: choose the Mandarin “can”

9. Potential complements with objects

Objects can make potential complements harder because Mandarin often wants the verb-complement unit to stay together. Compare:

这篇文章我看得懂。
Zhè piān wénzhāng wǒ kàn de dǒng.
I can understand this article.

我看得懂这篇文章。
Wǒ kàn de dǒng zhè piān wénzhāng.
I can understand this article.

Both can work, but topic-fronting the object is often very natural, especially when the object is known:

这个字我写不对。
I can’t write this character correctly.

这句话我听不懂。
I can’t understand this sentence when I hear it.

这件事我说不清楚。
I can’t explain this matter clearly.

This connects potential complements to topic-comment structure. Mandarin often brings the problem object forward, then comments on whether the speaker can achieve the result.

A useful pattern:

Object/topic + subject + V不C

Examples:

这个菜我吃不完。
I can’t finish this dish.

这扇门我打不开。
I can’t open this door.

这个问题我回答不上来。
I can’t answer this question.

10. High-frequency fixed-feeling potential forms

Some potential complements are so common that learners should memorize them as everyday chunks.

Not all of these should be analyzed from scratch every time. But the 得/不 potential logic helps learners see why they cluster around possibility, capacity, tolerance, affordability, and necessity.

11. Potential vs permission in public signs

Signs often use different structures depending on whether the issue is physical possibility or rules.

门打不开。
The door cannot be opened.  (physical/functional problem)

禁止开门。
Opening the door is prohibited.  (rule)

不得入内。
Entry is not permitted.  (formal rule)

进不去。
Cannot get in.  (practical impossibility)

Learners should not translate all of these as “can’t.” The reason for “can’t” matters.

Module name: English “Can” Splitter

User flow:

1. User sees an English sentence with “can/can’t.”
2. Tool asks: Is this skill, permission, physical possibility, result achievement, or formal rule?
3. User selects Mandarin structure: 会, 能, 可以, V得C/V不C, 不得.
4. Tool shows natural examples and common wrong choices.

Advanced mode: Convert result/direction complements to potential forms:

听懂 → 听得懂 / 听不懂
做完 → 做得完 / 做不完
进去 → 进得去 / 进不去
看出来 → 看得出来 / 看不出来

Remediation pass: split English “can” before teaching potential complements

This article needs strong remediation because English “can” maps to several Mandarin structures. Learners often overuse 可以, underuse V得C/V不C, and confuse actual outcome with potential.

Start by banning one mental shortcut:

English “can” does not equal 可以.

Then give the split.

This table is the whole article’s anchor.

The base chain: 看懂 → 看得懂 → 看不懂 → 没看懂

Use one verb-complement pair and expand it.

The difference between 没看懂 and 看不懂 is crucial:

我没看懂。
I didn’t understand it. Maybe I can if I reread.

我看不懂。
I can’t understand it. It is beyond me / not legible / not comprehensible.

Potential complement as “verb-specific possibility”

V得C/V不C says whether a result can be achieved through that verb under the circumstances.

听得懂      can understand by listening
听不懂      cannot understand by listening
买得到      can obtain/buy
买不到      cannot obtain/buy
进得去      can get in
进不去      cannot get in
做得完      can finish doing
做不完      cannot finish doing

The result complement supplies the target outcome; 得/不 says whether the path to that outcome is open.

能 + result complement vs V得C

Both can be possible, but they do not always feel identical.

The article should not overstate the difference as a rigid rule. It should present the contrast as a default feel that native examples can sharpen.

会, 能, 可以 in learner traps

得 and 不 in potential complements are not degree complements

Learners see 得 and remember 说得很好. That is a different structure.

Context often disambiguates, but the article should include a sidebar:

V得 + adjective can describe degree.
V得 + result complement can express potential.

Compare:

他说得很清楚。
He speaks/explains very clearly.      (degree)

这个问题他说得清楚。
He can explain this issue clearly.    (potential/result; context-dependent)

这个问题他说不清楚。
He cannot explain this issue clearly.

不得: formal prohibition and fixed forms

不得 is not the normal spoken negative of 得 in potential complements. In modern written Mandarin it often appears in formal prohibitions or fixed expressions.

非工作人员不得入内。
Unauthorized personnel may not enter.

未经许可，不得转载。
May not be reproduced without permission.

不得不
have no choice but to

Learners should not use 不得 as a casual replacement for 不能.

Expanded practice: choose the right “can”

Expanded module: English “Can” Splitter

The module should begin with an English sentence using “can/can’t” and ask what kind of “can” it is.

Flow

1. Show English prompt: “I can’t get in.”
2. User chooses category: skill / permission / possibility / result availability / formal rule.
3. Tool suggests Mandarin: 我进不去。
4. Tool contrasts with wrong choices:

• 我不会进去 = I do not know how to go in? strange.
• 我不可以进去 = I am not allowed to go in.
• 我不能进去 = broad cannot; possible, but less specific than 进不去.

This tool would be high-value because English “can” errors are persistent even among otherwise strong learners.

• Mandarin grammar references describe potential complements as structurally related to result and directional complements, formed by inserting 得 or 不 between the verb and complement.
• Learner materials should distinguish 能, 会, 可以, and potential complements because English “can” collapses these categories.