My English speaker friends said I can't say:
I have 1 hour left until/till going home.
My friends recommended to use this:
I have 1 hour left until/ till I go home.
But I can say this, right?
I have 1 hour left before going home
Then even though in sentence 1 and 3, until and before are both prepositions, why can't I use gerund behind until and till?