My English is not very good... Different tone, exist in the first Chinese sentences mean different situation. "What" read on behalf of:
1. According to ask someone, something, or something of themselves or properties. For example: have you got any news from there?
2. Ask something or something. For example: tell me what are you looking for?
3. Said no. For example: what is he? You miss him!
4. The blame. For example: what are you laughing at?
(only three usages of cited a total of 10)
What does the sentence according to said tone weight can tell:
1. 什么 tone is light, said:' what things do you know(about sth.)?"
2. 什么 tone heavier, said:"what things that you know!"
Hope useful to you, I'm just a junior school students.