inductors usage

hi
I've studied the inductors and it's laws in the college,
but I didn't know the main usage of it in the practical applications,
could you please tell me where I can use it.
I'm sorry for my weak english

Filters (low/high pass)
Energy Storage (SMPS)
Transformers

Probably transformers in the main AC power lines are the most common use of inductors. It's what steps the 10,000V (or whatever the power company sends down the lines) into the 120V/240V that comes out of your wall. THey are also used in high frequency amplifier circuits because they add a zero to counter the poles produced by the capacitors. This increases the frequency response of the circuit at higher frequencies