[Q] Given the sentence "The large brown dog with the red collar is in the grass." is it true that "The dog lost its collar."?
[A] The dog can't have a red collar while having lost its collar.
The answer is no.

[Q] Premise: "A man is riding a bike down a dirt trail."
Hypothesis: "Professional bike rider races down winding path on mountain."
Do we know that the hypothesis entailed by the premise?
[A] Not all man riding a bike down a dirt trail is professional bike rider.
The answer is it is not possible to tell.

[Q] Given the sentence "Two children laying on the ground smile at each other." is it true that "Two children are laying on the ground watching the clouds."?
[A] The children may be smiling for other reasons and may or may not be watching the clouds.
The answer is it is not possible to tell.