What is used to ask about a thing or an action:  What is this? It's my new car.  What are you doing here? I am waiting for Mary.


  Who is used to ask about a person:  Who is that boy?  My brother Tom.


  Where is used to ask about a place:  Where are my glasses?  On the table.

When is used to ask about time:

When do some trees lose their leaves? In autumn.

  Whose can be used  as a determiner (before a noun) or as a pronoun. It is used to ask which person something belongs to or is associated with: Whose car is this? It´s Sheila´s.     Whose is this coat? It's Peter's.


  Which can be used as a determiner or as a pronoun. It is used to ask about one thing or person when the choice is restricted: There are three coats on the chair. Which one is yours?


  Why is used to ask the reason for something of the purpose of something: Why is Sally crying? She is crying because she has cut herself.


  How is used to ask about manner:  How do you come to school? By bus.

  How can be combined with other words at the beginning of questions:

How much is used to ask about the amount of something: How much milk is there in the fridge?  Two litres.

How many is used to ask about the number of things or people:  How many bottles of milk did you buy?  Three bottles.

How long is used to ask about the length of a period of time: How long have you lived here? For two years.

How far is used to ask about distance: How far is it to London from here? 500 km.