advice是用 a 还是an 还有 E-mail advertisement E-cat
问题描述：
advice是用 a 还是an 还有 E-mail advertisement E-cat
答
advice建议,为不可数名词,一条建议：a piece of advice
E-mail advertisement E-cat前用an
tips：元音因素开头的名词前用an,辅音因素开头的名词前用a