(1) The reason for the outbreak: The Paris Peace Conference rejected China's just demand and unreasonably handed over the privilege of German occupation of Shandong before World War I to Japan. (3 points, 2 points in the previous sentence and 1 point in the latter sentence)

(2) "Enemy of the people" refers to Japan. ( 1)

(3) Slogan: "Fight for sovereignty from outside, and reject national thieves from inside." ( 1)

(4) The spirit of the May 4th Movement: patriotism, fearlessness of violence, courage of sacrifice and heroic struggle. (2 points, one point for all points)

This question examines the May 4th Movement. Reasons for the May 4th Movement: The Paris Peace Conference rejected China's just demand and unreasonably handed over the privilege of German occupation of Shandong before World War I to Japan. The "national enemy" in Material 3 refers to Japan. The slogan that best embodies the nature of the May 4th Movement is "Fighting for sovereignty outside and getting rid of national thieves inside." May 4th spirit: patriotism, fearlessness of violence, courage of sacrifice and heroic struggle.