It can be difficult to know the difference between ‘which’ or ‘that’ and when to use either in a sentence. Both sound like they can easily be swapped out for each other depending on your mood.
But there’s one general rule. ‘That’ is for a restrictive cause and ‘which’ is for a non-restrictive clause.
What does this mean?
- Use ‘that’ when needing to define the subject of the sentence. For example, ‘The fabrics that I need to sew my dress are expensive.’ The phrase ‘that I need to sew my dress’ defines which fabrics are expensive. Without the ‘that’ the sentence will imply all fabrics are expensive.
- Use ‘which’ when it won’t change the meaning of the sentence when removed. For example, ‘The needle, which I use for sewing my dress, rolled off the table.’ Removing the phrase, ‘which I use for sewing my dress’ doesn’t change the meaning of the sentence (the needle falling off the table).
So now that you know the difference, you will know which one to use in a sentence (see what I did there).