Title: Anti-aircraft warfare.
Question: While light, the Bofors 40mm were powerful enough to take down what size aircraft?

Title: Frédéric Chopin.
Question: Which two of Chopin's friends became part of his Paris milieu?

Title: Anti-aircraft warfare.
Question: Who wanted the British to keep using machine guns in World War I?

Title: FC Barcelona.
Question:
What title did Barcelona win in 1999?