# when they are crouching ... to lie in wait?

"You know that you cannot hunt down ... when they are crouching ... to lie in wait.". The question that began with the words "Can you hunt" in verse 39 ends here.

# dens

A "den" is a lair or shelter where lions live.

# sheltering in hiding

"hiding in a thicket." Lions hide in thick vegetation when hunting their prey.

# to lie in wait

"to lie waiting for a victim"