I work - Do you work? - I don't work / he works - Does he work? - He doesn't work
When do you use the present simple?
permanent situations / factsExample: Water freezes at 0 degrees Celsius.
Habitual situations / habits (sometimes, often, usually etc)
Example: I usually do my homework before supper.
In time clauses (once, until etc)
Example: You stay at school until you finish this assignment.
In zero conditionals (if/when + present simple, present simple: every time the first part happens, the second part happens too) = in effect a fact
Example: If the temperature drops below zero, water turns into ice.
In schedules, timetables
Example: the train leaves at 18. 45 from platform 3b.