What's the difference between opportunity costs and trade offs?

A trade-off describes what you sacrifice to get something else. Opportunity cost refers to what you could have done with what was given up. e.g. Somebody skips school to go see a soccer match. The trade-off is giving up school for seeing the match. Opportunity cost refers to what was given up, i.e. grades would not have suffered had the person in question not skipped school. This opportunity was given up by the person.
ex of trade off: A person may choose to sleep rather than going to class. That is Trade -Off
ex of opportunity cost: Shoes and bags, a person may prefer shoes more than bags because the cost is affordable and also of higher quality
Hope this helps!