instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Which analgesic drug, first isolated in 1804, was named after the Greek god of dreams ?
answer:
analgesic


question:
Christopher Eccleston, Kerry Fox and Ewan McGregor played flatmates in which 1994 film?
answer:
christopher eccleston


question:
IBM Halt is one of nine railway stations in which Clydeside town?
answer:

river clyde