Complex sentence: During the Second World War Amory served in military intelligence in the United States Army from 1941 to 1943 before joining the board of directors of the Humane Society of the United States in 1962, remaining there until 1970.
Split into simpler sentences: During the Second World War Amory served in military intelligence in the United States Army from 1941 to 1943. He joined the board of directors of the Humane Society of the United States in 1962, remaining there until 1970.