this is an onion and that is --- beef 横杠上添a an 还是/
问题描述：
this is an onion and that is --- beef 横杠上添a an 还是/
答
a
答
不填
beef是不可数名词
答
a
a/an由冠词后单词的音标的首音节是否为元音决定,不是就a,是就用an