who is talking?who are talking?哪个对

题目

who is talking?who are talking?哪个对
Tom,Mary and Peter are talking happily.主语划线提问，难道不是who are talking?

答案

who is talking 对 who可以看成是第三人称单数
你提问之前肯定不知道你问的“谁”是单数还是复数,难道一句话用单数还是复数还要根据回答来确定吗,这是不可能的.
who就是第三人称单数,所以用is