Question

펭귄은 수영을 할 줄 알지만 날지는 못해요 -(으)ㄹ 줄 알다/모르다 is a pattern expressing the subject's ability to do something or knowledge on how to do something. The pattern consists of the prospective modifier -(으)ㄹ followed by the noun 줄 ('the way', 'the fact') and the verb 알다 ('to know') or 모르다 ('to not know') in the present tense form.The -ㄹ 줄 알-/모르- form attaches to verb stems ending in a vowel or ㄹ, and the -을 줄 알-/모르- form follows stems ending in a consonant.Attached to a verb stem with the 알다/모르다 part in the present tense form, the pattern expresses the same meaning as -(으)ㄹ 수 있다/없다 in its 'ability marker' usage. The meaning of -(으)ㄹ 줄 알다/모르다 corresponds to 'know how to' and 'don't know how to'. The fact of (not) knowing how to do something implies the subject's (in)ability to perform the related activity.

Accepted Answer

Penguins can swim but cannot fly

Front	펭귄은 수영을 할 줄 알지만 날지는 못해요
Back	Penguins can swim but cannot fly
Notes	-(으)ㄹ 줄 알다/모르다 is a pattern expressing the subject's ability to do something or knowledge on how to do something. The pattern consists of the prospective modifier -(으)ㄹ followed by the noun 줄 ('the way', 'the fact') and the verb 알다 ('to know') or 모르다 ('to not know') in the present tense form. The -ㄹ 줄 알-/모르- form attaches to verb stems ending in a vowel or ㄹ, and the -을 줄 알-/모르- form follows stems ending in a consonant. Attached to a verb stem with the 알다/모르다 part in the present tense form, the pattern expresses the same meaning as -(으)ㄹ 수 있다/없다 in its 'ability marker' usage. The meaning of -(으)ㄹ 줄 알다/모르다 corresponds to 'know how to' and 'don't know how to'. The fact of (not) knowing how to do something implies the subject's (in)ability to perform the related activity.

줄 으)ㄹ 알다/모르다 Pattern Verb Subject's Present Tense