The adverse health effects of high-impact football tackles, which had been shown to harm football players' health by causing concussions and irreversible brain damage, have led parents and educators to engagein spirited debates about whether football should be banned in high schools across the country.
A. had been shown to harm football players' health by causing concussions and irreversible brain damage, have led parents and educators to engage in
B. were shown to harm football players' health
...
A. had been shown to harm football players' health by causing concussions and irreversible brain damage, have led parents and educators to engage in
B. were shown to harm football players' health
...
