Hi ! Here is my question: we can 'raise/lower' prices or 'put up/bring down' prices. However my teacher told me one of these groups of examples was slightly more formal, and can refer to a change in the level or standard of something as well as prices. Nevertheless, I can't remember which group it is. Is it the first two examples ('raise/lower') or the last two examples ('put up/bring down') ? Have a nice evening/day !