Lawrence Craven, a doctor from the USA, is the author of several published reports, one of _____ introduced the idea in 1953 _____ aspirin could reduce the risk of heart attacks.
________ London many times, but he knows little about the city.
. He is not ________ a fool ________.
Neither my father nor my brothers ______ the symbol.
This book can be used in ________ countries.
. After school, the students came home, ________.