how,why,when是特殊疑问副词，引导特殊疑问句:
其句式结构是：
“特殊疑问词+一般疑问句”
例句：
1.How did you get there?
2.Why are you late again?
3.When will you go to Shanghai?
what 是疑问代词，在句子中可作主语，也可作宾语。当疑问代词作主语时要用陈述语序，不作主语时要用疑问语序。例句：
1.What makes you think I am a doctor?
疑问代词what作主语用陈述语序。
2.What did you do last Sunday?
疑问代词作宾语要用疑问语序。
