So I am reading Hammer's German Grammar and it says:
Kosten and lehren are normally used with two accusatives:
Der Flug hat meinen Vater 5000 Euro gekostet
The flight cost my father 5000 euros
How are these two accusatives, I only see one accusative here and that is 5000 euros.
Meinen Vater seems like an indirect object to me because it answers the question: To whom did the flight cost 5000 euros?
Sie hat mich Deutsch gelehrt.
She taught me German.
Same thing here. To whom did she teach German? To me, so it should be mir right?