to turn over (face down); to lay face down; to lay upside down
to point downwards (eyes, head, etc.); to cast down (eyes)
to lie (one's body) face down; to lie flat (on the ground)
to conceal; to hide; to keep secret; to place in hiding (e.g. troops for an ambush)
to lie down; to retire; to go to bed (with an illness)
目を伏せて考えた。
I lowered my eyes and thought.
彼女は読み終えた本を伏せた。
She laid the book she had finished reading face down.
疲れた彼は机に顔を伏せている。
Tired, he has his face down on the desk.