When to use I at end of sentence?

You use "I" at the end of a sentence when it is the subject of the sentence and the sentence is in the first person.

Here are some examples:

* "It was I who did it." (Here, "I" is the subject of the verb "did".)

* "This is my favorite book, and I love it!" (Here, "I" is the subject of the verb "love".)

Important Notes:

* Formal vs. Informal: While grammatically correct, it is often considered more formal to use "I" at the end of a sentence. In casual conversation, it is more common to use "me." For example, you might say "It's me," but in a formal setting, you would say "It is I."

* After prepositions: After prepositions like "to," "for," "with," etc., it is usually more natural to use "me" even if it is the subject. For example, "The teacher gave the book to me."

Let me know if you have any other questions!