Middle School - Grade 7
Lesson 1: Ability & Inability
-(으)ㄹ 수 있다 (can) / -(으)ㄹ 수 없다 (cannot)
What Can You Do?
This grammar pattern is a direct translation of "to have the ability to" or "to not have the ability to."
수 means "ability" or "way."
있다 means "to have."
없다 means "to not have."
Literally, you're saying "I have the ability to..." or "I don't have the ability to..."
Conjugation Rules
You attach this to the verb stem, just like the future tense `-(으)ㄹ 거예요`!
Rule 1: Stem ends in a VOWEL or `ㄹ`
Add -ㄹ 수 있다 / -ㄹ 수 없다 to the stem. (If it ends in `ㄹ`, just add ` 수 있다/없다`.)
가다 가 + ㄹ 수 있다 갈 수 있어요 (I can go)
만들다 만들 + 수 있다 만들 수 있어요 (I can make)
Rule 2: Stem ends in a CONSONANT (except `ㄹ`)
Add -을 수 있다 / -을 수 없다 to the stem.
먹다 먹 + 을 수 없다 먹을 수 없어요 (I can't eat)
Example Sentences
Can (`-ㄹ 수 있다`)
- 운전할 수 있어요. (I can drive.)
- 한국어를 읽을 수 있어요. (I can read Korean.)
- 지금 만날 수 있어요? (Can you meet now?)
Cannot (`-ㄹ 수 없다`)
- 매운 것을 못 먹어요. (I can't eat spicy food.)
- 이해할 수 없어요. (I can't understand.)
- 내일 갈 수 없어요. (I can't go tomorrow.)
Bonus: The Other "Can't" (`못`)
There is a shorter, more common way to say "cannot" for actions: `못`. You place it *before* the verb.
| Grammar | Meaning | Example |
|---|---|---|
| -(으)ㄹ 수 없다 | "Not have the ability to" (General inability) | 수영할 수 없어요. (I can't swim.) |
| 못 + Verb | "Cannot do" (More common, conversational) | 수영 못 해요. (I can't swim.) |
Key Difference
They are very similar, but `-(으)ㄹ 수 없다` can sound a bit more formal or emphatic. `못` is extremely common in daily speech.
Rule for `못`: For `하다` verbs, `못` goes *between* the noun and `하다`. Example: 운전 못 해요 (I can't drive.)