(으)ㄹ 줄 알다/모르다

Overview

The grammatical expression (으)ㄹ 줄 알다/모르다 is used to indicate whether a subject knows how to perform a specific action or possesses a particular skill, or does not know how to. It specifically refers to learned abilities or practical know-how, rather than simple factual knowledge or physical capability.

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Usage

This pattern is attached to verb stems to express competence or lack thereof in an action.

• Use (으)ㄹ 줄 알다 when the subject knows how to do something.
• Use (으)ㄹ 줄 모르다 when the subject does not know how to do something.

It's crucial to understand that (으)ㄹ 줄 알다/모르다 is distinct from other expressions of ability like -을 수 있다/없다. While -을 수 있다/없다 generally refers to the possibility or physical capability to do something, (으)ㄹ 줄 알다/모르다 specifically addresses the knowledge or skill required to perform an an action. For example, you might be able to (할 수 있다) lift a heavy box, but you might not know how to (할 줄 모르다) fix a car.

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Conjugation Rules

The conjugation depends on whether the verb stem ends in a vowel or a consonant.

1. Verb stem ends in a vowel or ㄹ: Add -ㄹ 줄 알다/모르다.

   • Example: 하다 (to do) -> 할 줄 알다/모르다
   • Example: 만들다 (to make) -> 만들 줄 알다/모르다 (Note: ㄹ-ending verbs follow the vowel-ending rule)

2. Verb stem ends in a consonant (excluding ㄹ): Add -을 줄 알다/모르다.

   • Example: 읽다 (to read) -> 읽을 줄 알다/모르다
   • Example: 먹다 (to eat) -> 먹을 줄 알다/모르다

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Knowledge Plus

While (으)ㄹ 줄 알다/모르다 is primarily for expressing learned skills, it can also be used in certain contexts to express expectations or predictions about future events, especially in negative forms. For instance, "그렇게 될 줄 몰랐어요" means "I didn't know it would turn out that way" or "I didn't expect it to happen." However, its core meaning remains centered on "knowing how" or "not knowing how."

Common mistakes to avoid:

• Do not confuse it with -을 수 있다/없다. Remember, (으)ㄹ 줄 알다/모르다 is about skill/knowledge, while -을 수 있다/없다 is about possibility/capability.
• Ensure correct conjugation based on the verb stem's final sound.