Student: Given the sentence "Three girls are sitting our on the sand at the beach posing for the camera." is it true that "Three girls are on the sand."?.
Teacher: Let's think:

If you are sitting on sand then you are on the sand. So the final answer is yes.
Student: Given the sentence "Three girls are sitting our on the sand at the beach posing for the camera." is it true that "Three girls are on the sand."?.
Teacher: Let's think:

user
If you are sitting on sand then you are on the sand. So the final answer is yes.
assistant
Student: Given the sentence "Three girls are sitting our on the sand at the beach posing for the camera." is it true that "Three girls are on the sand."?.
Teacher: Let's think:

If you are sitting on sand then you are on the sand. So the final answer is yes.