�?블로�?전체 카테고리 글 전체글 보기 화면 최상단으�?이동 If a grammatical basic principle that is definitely extra to 서툴�?is usually a vowel �?and there's no other solution apart from a vowel �?then that grammatical basic principle can't be additional to 서툴�? 위의 자료들을 근거�?하여