past simple

USE
THE PAST SIMPLE IS USED FOR AN ACTION WHICH HAPPEND AT A DEFINITIVE TIME IN THE PAST. THE TIME IS STATED, ALREADY KNOWN OR IMPLIED

EX. THEY SPENT THEIR HOLIDAYS IN SWITZERLAND LAST WINTER(WHEN DID THEY GO TO SWITZERLAND?. LAST WINTER. THE TIME IS STATED) THEY HAD A GREAT TIME (THE TIME IS ALREADY KNOWN

-- FOR ACTIONS WHICH HAPPEND INMEDIATELY ONE AFTER THE OTHER IN THE PAST
EX. FIRST HE READ THE MESSAGE, THEN, HE CALLED HIS BOSS

--FOR PAST HABITS OR STATES WHICH ARE NOW FINISHES IN SUCH CASES WE CAN ALSO USE THE EXPRESSION USED TO
EX. PEOPLE TRAVELLED/USED TO TRAVEL BY CARRIAGE IN THOSE DAYS