- 비말은 비오일성(기름입자가 아님)이므�? 오일 성분�?차단능력은 크게 중요하지 않다. If a grammatical principle which is added to 서툴�?is a vowel �?and there's no other alternative other than a vowel �?then that grammatical basic principle can not be added to 서툴�? It really is incorrect to