human
How do I know when to use the word "that" vs. "which"?
assistant
That is a tricky question!  I think that it depends on the context of your sentence, and what you are trying to say. For example, if you were writing a story about a character who was looking for something in their house, you might say: “The cat jumped onto the bed and then ran across the blanket.” In this case, you would want to use “which” because you're talking about a specific item, not just any old blanket.