wait movement' end

[WiZ`]

like in the title... is possible in a script to insert an order for make the script wait the ending of the movement? like:
if input.trigger? (input::DOWN)
$game_player.move_down
$game_player.move_down
---wait for the movement to end---
end

a kinda of... pls help ^^
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sorry for my english, i know, it's orrible XD
but you see... i'm italian :\