proszę o wyjaœnienie rówżnicy

prosze o wyjaœnienie różnicy między tymi wyrazami :

1. electric/electrical ? (e.g. toothbrush)
2. spare/additional ? (e.g. parts to fix my TV)
3. (e.g. my printer doesn't) act/work

dzięki :)
pozdrawiam :)

It's not easy to explain them but as for 'electric/electrical' - 'electric' usually means 'using/consuming electricity', e.g.
electric toothbrush/engine/chair - all run on electricity
'electrical' has a more general meaning, but usually describes something that is somewhat connected with electricity, e.g.
electrical engineering/fault/circuit

dzięki :)

spare parts = more parts of the same kind (zapasowe)
additional parts = more parts, not exactly of the same kind (dodatkowe)
Compare:
There are some more additional parts for the bicycle like mudguards and a bell as well as some spare parts such as tyres, inner tubes and spokes.

(e.g. my printer doesn't) act/work

act is normally used with people performing an action:
She acted wisely.
Just act as you please.

but something/somebody can 'act as' = (działać/funkcjonować jako); 'act on' something else/somebody = (oddziaływać/działać/wpływać na coś/kogoś), e.g.
We hope the book will act as a bridge between doctor and patient.
... drugs which can act very fast on the central nervous system.

So you are to say 'My printer doesn't work.'