Wh-questions

There are eight wh-questions - what, when, where, which, who, whom, whose and why and to this list we usually add how as they are all used to elicit particular kinds of information.

You use what when you are asking for information about something. (O que, Qual)
You use when to ask about the time that something happened or will happen. (Quando)
You use where to ask questions about place or position. (Onde)
You use which when you are asking for information about one of a limited number of things. (Qual dentre as opções)
You use who or whom when you are asking about someone's identity. (Quem)
You use whose to ask about possession. (De quem)
You use why to ask for a reason. (Por que)
You use how to ask about the way in which something is done. (Como)

...

Então, dá uma olhada nesses testezinhos:

Teste 1
Teste 2

Enjoy!