Hello, fellas. In the previous session of #GrammarTrivia on June 11, 2019, we learned how the future is expressed in time clauses.
(More on the future in time clauses: https://englishtips4u.com/2019/06/15/grammartrivia-expressing-the-future-in-time-clauses/)
Our session today is about using the present progressive and the simple present to express the future.
The future is expressed by the present progressive when a sentence concerns a planned event or definite intention. Its future meaning is conveyed by future time words or the context.
My sister is seeing a doctor next Wednesday.
The simple present may also be used to express the future in a sentence if it concerns a definite schedule or timetable. It usually contains future time words. Only several verbs are used in this way, e.g., open, close, begin, end, start, finish, arrive, leave, come, return.
The competition starts tomorrow.
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition