Pomocy! Zupełnie nie wiem jak to rozgryźć...
That's the school which we attended when we were young.
GO That's the school we when we were young.
Nobody apart from Bill thought that it would work.
ONLY Bill thought that it would work.
Experts have estimated that more than half the population of the UK now own a mobile phone.
BEEN It more than half the population of the UK now own a mobile phone.