"Outside playing" is not a complete sentence on its own, but it can be used as a phrase in a sentence.
Example: The children were outside playing in the park while their parents relaxed on a bench nearby.
"They were outside playing.
"The kids would be playing outside, playing basketball," he said.
I was taking naps in the afternoon while all my friends were outside playing.
Instead of jamming pitcher Julian Tavarez inside, he threw outside, playing to Tavarez's strategy.
I'm working hard on dealing with surprises on court but, outside playing, they can be tough.
The Kid, bundled in a spacesuit, is outside playing catch with an asteroid.
One hot summer day, she said, she was watching her 6-year-old daughter outside playing.
"The minute he got the cast off," Cisco said, "he was right back outside playing again".
When the twins were outside playing ball with friends, Nick would cramp up and become rigid like a statue.
Students peered out the windows of the Harlem school as angry protesters waited outside, playing bongos and waving signs.
It was a brilliant day blue skies, everyone outside playing Frisbee, and even the grown-ups were in a good mood.
