필요�?서식 자료 역시 서식 자료실을 통해�?무료�?내려받을 �?있다�?합니�? If a grammatical principle which is additional to 서툴�?is usually a vowel �?and there is no other solution in addition to a vowel �?then that grammatical basic principle can not be extra to 서툴�? 자격득실 확인�