Które ze słów poprawnie uzupełnia zdanie? Wpisz je poniżej.

1 One side of the hill was quite flat / steep / rough, so we had no problems climbing up to the top. 
2 I don’t think we should go sailing today. I’ve seen the weather prediction / knowledge / forecast and it’s going to rain later. 
3 There was no wind so the surface of the sea was perfectly shallow / calm / rough.