[Q]: The friends' debate dragged on interminably.

cause: 
[A]: The friends were splitting hairs.
[Q]: Air leaked out of the beach ball.

cause: 
[A]: There was a hole in it.
[Q]: The friends' dinnertime conversation turned to politics.

effect: 
[A]: A debate erupted.
[Q]: I received a package in the mail.

effect: 
[A]:
The package triggered my curiosity.