Thank you very much! I still have a few other sentences I'm not sure of.

1) "Lost" was popular because it had (not it has?) an unusual plot.
(also: because of its unusual plot).
2) Forty-eight out of three hundred and twenty passangers survived the crash.
3) By the time they learnt their new parents and when they came back home, they were better than before.
4) By the time or with time/little by litte/eventually they learnt to respect... (?)and were better behaved than before.

1. Yes, past tense.

2. OK

3. I don't understand "they learnt their new parents"

4. Over time, they learned to respect their parents and were better ...