What Are Their Main Differences?
The key difference between 'what' and 'which' relies on what they refer to. Actually, 'what' refers to an open set of options, while 'which' is used for a closed set.
Although, you can use 'what' and 'which' interchangeably, there are certain examples where only one of them can be correct.
Use What for Unlimited Answers and Which for Limited Answers
is used to ask questions when there are lots of answers. For example, when you ask; 'What is your favorite color?' the person can name many different colors.
is used when the answers are fewer, so they are limited. For example, when you ask; 'Which of your children is going to ballet class?'
Whenever you know something already, or you have knowledge about the choices in advance, 'which' is a better option to use.
How They change the Whole Meaning
Since 'what' refers to more options than 'which' they can subtly change the whole meaning of the sentences. Look at the examples to be clarified.
What and Which as Relative Pronouns
- 'Relative pronouns':
Whenever a relative pronoun, referring to actions and things, is required; we need the relative form of 'what', which is the word 'that', while the relative pronoun of 'which' is the term 'which'.
The small animal
What, Which, or Both?
Whenever there are several options but not infinite choices, either 'what' or 'which' will work perfectly.