A Wizard of Mars originates from the United States, where English (language of Great Britain) is spoken. Barack Obama was the previous leader of the US and African Americans are an ethnic group there.
[['United States', 'ETHNIC_GROUP', 'African Americans'], ['United States', 'LEADER_NAME', 'Barack Obama'], ['English language', 'SPOKEN_IN', 'Great Britain'], ['United States', 'LANGUAGE', 'English language'], ['A Wizard of Mars', 'COUNTRY', 'United States']]