This pattern indicates something is not what was expected.

- can be used with any verb
- similarly 은 고사하고 attaches to nouns ending in a consonant and -는 고사하고 attaches to nouns ending in a vowel
- is interchangeable with -기는 커녕 but -기는 커녕 is less colloquial

Examples:
친구의 병이 낫기는 고사하고,더 심해 졌습니다./Instead of recovering, my friend's illness got worse.
그 것을 먹기는 고사하고, 맛도 보지 못했어./Far from eating it, I couldn't even try it.