The particle UP means:
– towards a higher place
– make bigger
– to a centre
The particle DOWN means:
– towards a lower place
– make smaller
So when I say “I picked up the book from the floor”, it means I moved the book to a “higher place”. However, when I say “I live in Bristol but I go up to London regularly”, it doesn’t mean that London is in a higher place, but rather to describe London as the political and economic center of England is “higher in importance” than other towns.
They decided to pull down the ruined building.
We use the particle down with the verb pull, NOT up (pull up) because buildings normally stand up in the air. So when the ruined buliding was pulled down, it means it was brought to the grown; it was destroyed.
She cut up the carrots and put them in the pan.
We use the particle up in cut up to mean that the carrots were cut completely to small pieces.