第二次世界大战的起点问题,迄今尚无定论,检视国内外学术界观点,共有以下五种说法:(一)三九说,以1939年9月1日希特勒德国入侵波兰,作为第二次世界大战的起点。与此相近的还有以1939年9月3日为起点的。(二)三五——三七说,认为在西方开始于1935年意大利对埃塞俄比亚的侵略和1936年德、意对西班牙的武装干涉,在东方开始于1937年7月日本法西斯侵占北京、上海。(三)三七说,认为“1937年7月7日芦沟桥事变,……就标志着第二次世界大战的正式开始。”(四)四一说,以1941年12月8日“珍珠港 The starting point of the Second World War has so far been inconclusive. Examining the views of academics at home and abroad has the following five views: (1) Sanjiu said that Hitler Germany invaded Poland as the second time on September 1, 1939 The starting point of world war. Similar to this and September 3, 1939 as a starting point. (Two) thirty-five - three seven said that in the West began in 1935 Italy’s aggression against Ethiopia and Germany in 1936, intended to intervene in Spain’s armed intervention in the East began in July 1937 Japanese fascists invaded Beijing and Shanghai. (3) Sanchi said: ”The Lugouqiao Incident of July 7, 1937, marked the official start of World War II.“ (4) According to the statement of ”four one,“ December 8, 1941 ”Pearl Harbor