[Q] Given the sentence "Two young men pretend to attack a third man with a colorful prop knife." is it true that "Three people are in a play."?
[A] Two men attacking a third with a prop knife does not imply that they are in a play.
The answer is it is not possible to tell.

[Q] Premise: "An older man with a white beard stands in front of a mast on a large sailboat."
Hypothesis: "While holding a rope."
Do we know that the hypothesis entailed by the premise?
[A] A man with a beard stands in front of a mast.
The answer is yes.

[Q] Premise: "A computer lab in a school."
Hypothesis: "Five people pictured."
Do we know that the hypothesis entailed by the premise?
[A] The children looked at the five people in a picture on a school computer.
The answer is it is not possible to tell.