QUESTION: Given the sentence "Two boys pose in front of a prehistoric garden sign that is attached to a chain link fence." is it true that "While shrubbery grows in the background."?

Let's solve it slowly: Two girls are sitting in front of a garden sign outside.
The answer is no.

QUESTION: Given the sentence "The boy wearing the blue shirt is running on the grass between the trees." is it true that "The boy is outside."?

Let's solve it slowly: A boy can run inside a garden can not be outside.
The answer is yes.

QUESTION: Given the sentence "Three people are harvesting grass from muddy water." is it true that "Fieldworkers are harvesting rice in a paddy."?

Let's solve it slowly:
Three people are harvesting grass from muddy water does not indicate that Fieldworkers are harvesting rice in a paddy.
The answer is it is not possible to tell.