Potential Complements: 得 and 不 Inside a Complement (看得懂, 拿不动)

You've now met resultative complements (看完, 听懂) and directional ones (出来, 下去). The potential complement is a small twist on both: slip 得 or 不 inside the compound, and it turns into "can" or "can't" achieve that result. 看懂 ("understand") becomes 看得懂 ("can understand") or 看不懂 ("can't understand"). It's a tidy, powerful pattern. Here's how it works.

The basic shape

Take any verb-plus-complement and wedge 得 (for "can") or 不 (for "can't") between the two halves:

verb + 得/不 + complement

• 看得懂 — can understand (by reading)
• 看不懂 — can't understand
• 听得懂 — can understand (by hearing)
• 拿得动 / 拿不动 — can / can't lift it

The 得 here is pronounced de, neutral tone, the same particle you've seen elsewhere. It signals possibility. 不 signals impossibility.

Why not just use 能?

You might wonder why this exists when 能 already means "can." Two reasons.

First, the potential form is the natural way to talk about achieving a result. When the "can" is about reaching an outcome, like finishing, understanding, or lifting, Chinese prefers the potential complement.

• 这本书我看得懂。 — I can understand this book.

Second, and this is the big one: the negative potential form is extremely common, often more so than the positive. 看不懂 ("can't understand") is heard constantly, much more than its positive twin.

• 太重了,我拿不动。 — It's too heavy, I can't lift it.
• 这个字太小,我看不清楚。 — The characters are too small, I can't see clearly.

The "can't" form is the star

In real speech, the negative potential is everywhere because it expresses a very natural idea: you tried, or you'd like to, but the result is out of reach.

• 吃不完 — can't finish (eating it all)
• 买不到 — can't manage to buy (it's sold out)
• 找不到 — can't find
• 听不见 — can't hear
• 起不来 — can't get up

Notice these aren't about permission or skill. They're about whether the outcome is reachable given the circumstances. 买不到 doesn't mean you're forbidden to buy or don't know how; it means you tried and the thing wasn't available.

Telling it apart from "didn't"

This is the key distinction, and it's the same one from the resultative article. Compare three forms of 看懂:

• 看懂了 — understood (it happened)
• 没看懂 — didn't understand (this time it didn't happen)
• 看不懂 — can't understand (not able to, in general)

English smears all of these into "didn't get it" or "can't get it," but Chinese keeps them separate. 没看懂 is a one-time miss; 看不懂 is an ongoing inability. Mixing them up is a classic error, so it's worth pausing on:

• 这个字我没看懂。 — I didn't understand this character (just now).
• 这个字我看不懂。 — I can't understand this character (it's beyond me).

Asking questions

To ask "can you?", use the A-not-A pattern on the complement: put both the 得 and 不 versions together.

• 你看得懂看不懂? — Can you understand it or not?
• 你听得懂吗? — Can you understand?

Both work. The 吗 version is shorter and more common in casual speech.

Common potential complements to know

A few of these come up so often they're worth memorizing as set phrases:

• 看得见 / 看不见 — can / can't see
• 听得懂 / 听不懂 — can / can't understand (heard)
• 买得起 / 买不起 — can / can't afford
• 来得及 / 来不及 — there's / isn't enough time
• 受不了 — can't stand it

That 买得起 / 买不起 pair is especially handy: 起 here means affordability, so 买不起 is "can't afford it," not "can't find it."

• 这个太贵了,我买不起。 — This is too expensive, I can't afford it.
• 快点,要来不及了。 — Hurry, we're going to run out of time.

A note on 把

The potential complement doesn't combine with the 把 construction. 把 is for actively completing something to an object, while the potential form is about whether you can, so the two clash. If you want to say you can't finish the homework, you say 我做不完作业, not a 把 sentence.

A quick recap

Wedge 得 or 不 inside a verb-complement compound to mean "can" or "can't" reach that result: 看得懂 (can understand), 拿不动 (can't lift). The negative form is the workhorse here, covering things like 找不到 (can't find) and 买不起 (can't afford). Keep it apart from 没 ("didn't happen"): 看不懂 means you're unable, 没看懂 means you missed it this once. Learn the common pairs and you'll reach for this pattern all the time.