strange idioms?

[Gość: Zgredek]

What does each idioms mean?
To be a wet blanket
Back-seat driver
to steal a show/spotlight?
Please if you can try translating it in to Polish!!!Thanks a lot.
Apart from i wrote above do I use translate in correct form(I mean in
contionoius)?

[alex113]

> Back-seat driver - pasazer ktory probuje "prowadzic" samochod pouczajac
kierowce co ma robic

> to steal a show/spotlight? - Przyciagnac na siebie cala uwage, (np osoba
ktora przyjdzie na slub kolezanki i swoim strojem i zachowaniem staje
sie "gwiazda" imprezy :-)

[alex113]

> To be a wet blanket - wet blanket puts down the fire, and a person who is
such kills all the entusiazm about current activity :-))