Complex sentence: He scored 1590 out of 1600 on the Scholastic Aptitude Tests and enrolled at Harvard College in the autumn of 1973, chose pre-law major but took most rigorous mathematics and graduate level computer science courses.
Split into simpler sentences: He scored 1590 out of 1600 on the Scholastic Aptitude Tests and enrolled at Harvard College in the autumn of 1973. He chose a pre-law major but took rigorous mathematics and graduate level computer science courses.