Paul/ always/ enjoy/ study/ sciences/ high school/ therefore/ decide/ major/ biology/ university/. A.  Paul always enjoys to study sciences in high school therefore decides majoring biology

Paul always enjoys to study sciences in high school therefore decides majoring biology at the university.

Paul always enjoys studying sciences at high school, He therefore decides to major on biology at university.

Paul always enjoyed studying sciences in high school. Therefore, he decided to major in biology in university.

Paul always enjoyed to study sciences in the high school; he, therefore, decided majoring at biology at the university.