A young girl in a polka dot dress plays on a beach is a synonym of a girl plays at the beach.
This justifies what answer for what question? Q & A: 
Given the sentence "A young girl in a polka dot dress plays on a beach." is it true that "A girl plays at the beach."?
yes
A young girl in a polka dot dress plays on a beach is a synonym of a girl plays at the beach.
This justifies what answer for what question? Q & A: 
user
Given the sentence "A young girl in a polka dot dress plays on a beach." is it true that "A girl plays at the beach."?
yes
assistant
A young girl in a polka dot dress plays on a beach is a synonym of a girl plays at the beach.
This justifies what answer for what question? Q & A: 
Given the sentence "A young girl in a polka dot dress plays on a beach." is it true that "A girl plays at the beach."?
yes