who在名词性从句中有表示疑问“谁”的意思（此点与定从不同）
如：The question is who will be the next speaker. 问题是谁接着发言。
what无疑问语气，如：That’s just what I want. 这正是我想要的。
特别注意what可相当于the thing/time/person/place/amount/number that
其次，what并不一定指物，如He is ____is known as a hacker- he likes to show off on the Internet and attack websites. 此处用what，因为无疑问语气
望采纳
