1. He discovered that American football players could suffer from a brain disorder previously found only in boxers. / His medical research put him on bad terms with one of America’s most powerful institutions, the NFL.
2. in disagreement with/on bad terms with
3. He was very hard-working and determined.
4. i) F ii) F iii) NG iv) T
5. He did not like the decisions the new Nigerian government was making/He did not like the new Nigerian government.
7. American football can be dangerous and players can suffer head injuries that could kill them.
9. Omalu believed the NFL would be interested in what he had learned about C.T.E, but they said his findings were "completely wrong" and "a failure".
10. 2, 4, 1, 3