(Grassy Stronghold isn't a spell.)
When Grassy Stronghold enters the battlefield, sacrifice it unless you pay 3 life.
, : Look at target player's hand.
: Add or to your mana pool.
Sacrifice Grassy Stronghold: Add or to your mana pool.
, 
: Look at target player's hand.: Add 
or 
to your mana pool. or to your mana pool.
