�?블로�?전체 카테고리 글 전체글 보기 화면 최상단으�?이동 If a grammatical principle which is extra to 서툴�?is usually a vowel �?and there's no other option apart from a vowel �?then that grammatical principle can't be additional to 서툴�? 의약품안전나�?의약품등검�? 의약�?사이�