cut sth down
- ograniczać, wycinać, skrócić - to make a tree or other plant fall to the ground by cutting it near the bottom
I think you should cut down hours you spend in front of computer screen.
cut down on sth
- ograniczać, redukować coś - to do less of sth or use sth in smaller amounts, to reduce suddenly the amount (of sth) used
I try to cut down on sweets and coffee.
The government has announced plans to to cut back on defence spending by 10% next year.
I\'m trying to cut down on caffeine.
:)