The ducks liked to swim. The ducks preferred to dive.
, but
The ducks need a diving board. The ducks will be bored.
, or
The cows gave duck the typewriter. Duck didn't return it.
The cows gave Duck the typewriter, but Duck didn't return it.
Duck knocked on the door. Duck handed Farmer Brown a note.
, and
Farmer Brown saw the letter. Farmer Brown could hardly believe his eyes.
Farmer Brown saw the letter, and he could hardly believe his eyes.