You were starting doing your homework when he came in. correct or not?

The sentence is grammatically correct, but it's a bit awkward. Here's why:

* The timing is unclear: It's not clear if "he" came in *while* you were starting your homework, or *after* you had already started.

* Passive voice: Using "was starting" is passive voice, which makes the sentence less direct.

Here are some ways to rephrase the sentence for better clarity:

* "He came in while I was starting my homework." (This makes the timing clear)

* "I was about to start my homework when he came in." (This emphasizes the interruption)

* "He came in, interrupting me as I began my homework." (This is more dramatic)

Choose the option that best fits the context of your story or conversation.