Question

ladon: (pointing offstage) look, mom! the human children are playing that stone - tossing game in the meadow again! see - that girl missed, so she lost her turn. she has to—
echidna: (serving ladon a plate full of worms) yes, yes. it all looks very interesting, ladon. but remember—human games are not for creatures like us. your time is better spent training for your future.
ladon: (complaining grumpily) im tired of learning how to scare off thieves. its not like anyone has stolen heras golden apples before.
what does ladons dialogue tell you about him?
he probably hopes to teach the children a game about monsters.
he has probably watched the children playing the game before.
he probably dislikes children and will try to scare them away.
he probably thinks the game is boring compared to the games he plays.

Explanation:

Ladon says "The human children are playing that stone - tossing game in the meadow again!" The use of "again" implies he has seen the children playing the game before.

Answer:

He has probably watched the children playing the game before.