"That"
* Essential (Restrictive) Clauses: Used for clauses that are essential to understanding the meaning of the main clause. They define or identify the noun they modify.
* Examples:
* "The book that I bought yesterday is very interesting." (You need the clause to understand which book is being discussed.)
* "The woman that lives next door is a doctor." (The clause identifies the specific woman.)
"Which"
* Non-Essential (Non-Restrictive) Clauses: Used for clauses that provide additional information but are not crucial to understanding the meaning of the main clause. They add details about a noun already identified.
* Examples:
* "The book, which I bought yesterday, is very interesting." (The clause adds extra information about the book, which we already know.)
* "My cat, which is a Persian, loves to sleep." (The clause provides additional information about the cat, which we already know.)
Key Differences:
* Commas: A comma is used before "which" in non-restrictive clauses but not before "that" in restrictive clauses.
* Specificity: "That" clauses specify the noun being referred to; "which" clauses add non-essential details.
Important Notes:
* Formal vs. Informal: In informal writing, "which" is sometimes used in place of "that" in restrictive clauses. However, this is not grammatically correct in formal writing.
* "Who" and "Whom": These pronouns are used for people in restrictive and non-restrictive clauses.
Example:
Let's say we are talking about a dog.
* Restrictive: "The dog that is barking is my neighbor's." (We need the clause to know which dog is being discussed.)
* Non-Restrictive: "The dog, which is a golden retriever, is very friendly." (We already know which dog we're talking about; the clause adds information.)
Let me know if you have any more questions!