Premise: "A young man is leaning on a tree in the grass and reading a book."\nHypothesis: "A young man leaning on tree."\nDo we know that the hypothesis entailed by the premise?
Let's think step by step.
it is not possible to tell
Someone leaning on a tree in the grass and reading a book is not just leaning on a tree.

.

Final answer: it is not possible to tell