"普遍" 是指(means;indicates) "大部分" (most part)。 例如,在台灣,大部分的人都騎機車上班。(For example, in Taiwan, most people go to work by scooter.) 或是(or), 在台灣,騎機車上班很普遍。(In Taiwan, going to work by scooter is very normal/common.)
"普及" 1.(popular) 是用在(is used)形容(describe)有很多人知道事或使用的東西。( things that many people know or use) e.g (例如:在現代,電視是普及的電器用品 / 家電用品。Nowadays, TV is a popular electrical appliance. )
2. (popularly) 用在 當什麼事情被很多人做或用時。(is used when things are done or used by people widely or usually.) 例如:在現代,網路已被普及使用。(For example: Nowadays, the Internet is popularly used.)
加油!! good luck!