Premise & hypothesis.
A BMX motorcyclist dressed in protective gear and helmet, attempting a jump on a sandy dune.

A BMX biker is riding on a dune.
++++++++++
true or not.
yes

Premise & hypothesis.
A boy in a striped shirt holds up a large black fish that he caught.

The boy went fishing.
++++++++++
true or not.
yes

Premise & hypothesis.
A young man performs a skateboard trick over some stairs.

A young professional skateboarder performing.
++++++++++
true or not.
it is not possible to tell