What is it called when two couples go out together for an evening?

Which word completes the British expression for a close escape from danger, "a narrow ___"? Which constructed language, introduced in 1887, has nouns that all end in "-o"? Many of Africa's Pygmy peoples, such as the Mbuti of the Ituri Forest, live in which country, once called the Belgian C… The largest share of people who applied for amnesty under the 1986 U.S. immigration reform lived in which state? A former DuPont chemist from New Hampshire introduced which brand of food storage containers in 1946? Which lively Spanish dance shares its name with a famous 1928 orchestral work by Maurice Ravel? What is an excess of revenues over expenses called in business? Which war ended with an armistice in November 1918?