Complex sentence: On January 3,1970 the first of four Boeing 727-100 entered into service and put to operate the trunk route Buenos Aires/Rio de Janeiro/Brasília and in 1975 the first Boeing 737-200 entered into service.
Split into simpler sentences: On January 3,1970 the first of four Boeing 727-100 entered into service and put to operate the trunk route Buenos Aires/Rio de Janeiro/Brasília. In 1975 the first Boeing 737-200 entered into service.