Premise & hypothesis.
A few men are shown flipping in the air, upside down, as a result of using a contraption that is on their legs.

Men jump up and down using a contraption
++++++++++
true or not.
it is not possible to tell

Premise & hypothesis.
A man grinding the lip of a pool on his Rollerblades.

A man is grinding in his rollerblades.
++++++++++
true or not.
yes

Premise & hypothesis.
Several people sit by a campfire in the darkness.

A group of people are around a campire roasting marshmallows.
++++++++++
true or not.
it is not possible to tell