Student: Is coming my new flatmate to live in my flat on Saturday.
Me: What did you say?
Student: Is coming-
Me: Wait!!! Stop!!!
Me: You can’t begin a sentence with the verb. Well, you can with an imperative, as I did just now when I said STOP! But in all the other sentences you need to put a subject before the verb.
Student: My new flatmate is coming to live in my flat on Saturday.