The field was safe, wasn't it?
Answer:
At length is more precise, at some length is defining a length that is unknown.
Explanation:
It was at length with the other car.
At some length, we will stop.
Answer:
It's because he sees the future as not as tragic as his past.
Explanation:
I think Grendel get stuck in a tree because of his careless curiosity of the world above him, that of the humans. He know nothing about that world because he was used to his own world in the underground however he still get tempted to explore. He was also attacked by a bull there because he looks different from the rest of the creatures above.