꼭 (kkok) which means 'exactly'; 'just'; 'without fail' is an adverb which occurs either before another adverbial expression or before an inflected expression. When it occurs before another adverbial expression, 꼭 means 'exactly' or 'just'; before an inflected expression it means 'without fail'. Compare the following : Group 1 'exactly' : 그것 은 꼭 내 가 원 하 는 물건 이다 (geu geoteun kkok nae ga won ha neun mul geon ida) = That is just [exactly] the thing I want. 강연은 꼭 1시간이 걸렸다 (kangyeoneun kkok 1shi gani geolryeossda) = The lecture lasted for just [exactly] an hour/The lecture lasted for one hour to the minute. Group 2 'without fail, surely, certainly, undoubtedly' : 꼭 오게 (kkok oge) = Never fail to come./Come without fail [by all means]. 꼭 가마 (kkok gama) = I will come, you may depend upon it. Group 3 'tightly; fast; firmly; securely' : 어머니는 자기 아이를 꼭 껴안았다 (eomeonineun jadi aireul kkok kkyeo anassda) = The mother hugged [embraced] her child tightly. Group 4 'tight(ly); closely' : 이 옷은 나에게 너무 꼭 낀다 (i oteun nayege neomu kkok kkinda) = This dress is too tight for me. Group 5 'as if; as though; just like; much[nearly] as; quite' : 하는 짓이 꼭 어린애 같다 (haneun jiti kkok eorinae galda) = He acts just like a child. Group 6 'patiently' : 웃음을 꼭 참다 (oteumeul kkok chamda) = hold back one's laughter In the sentences 꼭 도와 줘요 and 꼭 먹고 싶어요,, 꼭 means 'without failsurely, certainly, undoubtedly.( Group 2 )