1. 疑问代词做对陈述句的主语，宾语或定语提问，即做句子的主语，宾语或定语，如what, who/ whom, whose.
eg. Who is talking ? What can you see?
Whose shirt is this?
2.疑问副词对时间，地点，方式等状语提问，如when, where, how 等.
eg. When is your birthday? Where are you going?
How do you know?
常见的疑问代词：what  who  which  whom(只做宾语）
疑问副词：how  where  when
还有whether是疑问连接词。