‘Wh-’ words, or question words, are used to ask specific types of questions. The most common question words in English are ‘who’, ‘where’, ‘when’, ‘what’, ‘which’, ‘why’ and ‘how’.
‘Who’ is used when referring to a person. (I want to know the person.) Example: Question: Who is the woman in red? Answer: The woman in red is my sister.
‘Where’ is used when asking about places. (I want to know the place.) Example: Question: Where are you from? Answer: I’m from Canada.
‘When’ is used to refer to a time or an occasion. (I want to know the time.) Example: Question: When is your birthday? Answer: My birthday is in October.
‘What’ is used to refer to specific information or to ask about things or activities. (I want to know the thing.) Example: Question: What is your favourite colour? Answer: My favourite colour is blue.
‘Which’ is used when a choice has to be made. (I want to know the relevant alternative.) Example: Question: Which do you prefer, tea or coffee? Answer: I prefer tea.
‘Why’ is used to obtain a reason or an explanation. (I want to know the reason.) Example: Question: Why are you learning English? Answer: I’m learning English for work.
‘How’ is used to enquire about a method or the condition of something. (I want to know the way.) Example: Question: How do you know her? Answer: I met her at a party.