Prepositions of time (at/in/on) mastered through a set of rules or the point/period of time distinction by most, may still pose a problem.
Consider:
I’m going to the cinema at the weekend. (standard British)
I’m going to the cinema on the weekend. (common American)
I’m going to the cinema in the weekend. (at some point during the weekend)
lovely, isn’t it?
And how would you say “Rankiem, 20 września.” or “W nocy zamordował 6 osób”. Well, simple enough. It’s “On the morning of the 20th…” and “He murdered 6 people in the night”
