Premise & hypothesis.
A young man riding and grinding his skateboard against the railing.

A person is riding a green skateboard.
++++++++++
true or not.
it is not possible to tell

Premise & hypothesis.
Man studies a piece of music while learning how to play the ukulele.

The man is looking at sheet music.
++++++++++
true or not.
yes

Premise & hypothesis.
A man plays an accordion on a park bench.

The man is pregnant.
++++++++++
true or not.
no