Could you provide an example sentence? The only time gerunds can go without the "to be" verb is if they are acting as a noun, Example: I enjoy hiking. or if they are accompanied by another auxiliary verb. Example: I have gone hiking. I will try hiking. In all other cases I'm almost certain that a gerund must be accompanied by a form of "to be" acting as the auxiliary verb. Examples: I have been hiking. I will go hiking. I am hiking. She is hiking. Sometimes people will omit parts of the sentence in casual speech, which may have led to this observation. Example: Q-"where are you going?" A-"Hiking with my friends" The full answer without the casual omission would be "I am going hiking with my friends" If I have missed anything big here I trust the rest of the Italki community will shed some light on it, but I hope this answers your question :)

Hey! I am not a native speaker, but I read your question and thought about a few examples: *I'm not ok with you talking to me like that. *I don't see you doing your homework. Is this what you meant?