芬兰被称为世界上最幸福的国家

factor - n. something that helps produce or influence a result

editor - n. a person whose job is to edit something

rank - v. to place (someone or something) in a particular position among a group of people or things that are being judged according to quality, ability, size, etc.

contagious - adj. capable of being easily spread to others

Nordic - adj. of or relating to Sweden, Norway, Denmark, and sometimes Finland and Iceland, or to the people who live there

obesity - n. the condition of being fat in a way that is unhealthy

opioid - n. a class of drugs that are recommended to reduce pain

income - n. money that is earned from work, investments, business, etc.