第一次世界大戰問題.緊急!

1907年「三國協約」的簽訂，使歐洲正式分裂成為兩個敵對陣營：三國同盟與三國協約。

三國協約是指英國、法國和俄羅斯在1907年簽訂的互相諒解和互相支持的協議。「Entente」是法語詞匯，意指諒解。

The Triple Entente ("entente" — French for "agreement") was the alliance formed in 1907 among the United Kingdom of Great Britain and Ireland, the French Third Republic and the Russian Empire after the signing of the Anglo-Russian Entente. The UK already had the Entente Cordiale with France since 1904, while France had concluded the Franco-Russian Alliance in 1894.

1904年的摯誠協定及1907年的英俄條約簽訂後，英法、英俄的各種糾紛已經平息。這兩個協約，加上法俄同盟便促使三國家走在一起。此外，他們皆因為德國在歐洲的影響力不斷上升而警醒。因此，他們便結盟，名為「三國協約」。　　

三國同盟是德意志帝國、奧匈帝國和義大利王國在1882年5月20日簽署的條約，是一個軍事聯盟。三國同意任何一國被其他兩個或更多國家攻擊時協助對方。而且，德國與義大利約定，如果對方被法國攻擊，將會協助對方。然而，根據一項補充宣言，義大利的承諾不能被認定為針對英國。1902年6月，義大利延續同盟協定後，對法國許下了類似的承諾。


1915年的歐洲軍事聯盟。同盟國以深褐色表示，協約國以灰色表示，中立國以黃色表示。1881年5月，法國奪得突尼西亞這個義大利希望得到的殖民地。於是，為了得到支援，義大利加入德國和奧匈帝國的同盟，結為三國同盟。不過，義大利的民意並不太滿意與奧匈帝國結盟，因為她曾阻止義大利統一，並且仍然控制著被認為是「尚未收復的義大利」 (Italia irredenta)的特倫蒂諾和伊斯特拉。

值得注意的是，第一次世界大戰爆發的幾年前，很多著名軍事分析家都預測義大利會改變立場。1911年，義大利入侵並占領原本由奧斯曼帝國控制的的黎波里，令此預測更有說服力。而且，英國和法國在開戰後又作出承諾，會讓義大利獲得安那托利亞東南部，以及克羅埃西亞和斯洛維尼亞地區大部分領土。不過，英法在戰後並沒有兌現承諾。

1914年8月，世界大戰爆發，德國和奧匈帝國與英、法、俄三個協約國戰鬥。義大利保證支持同盟國，可是後來加入協約國陣營，先後在1915年5月和1916年8月向德奧兩國宣戰。

雖然義大利是被動的國家，但其希望保持歐洲均勢的意念，很明顯是傾向支持規模較大的同盟。她之所以不支持同盟國，是因為她們是主動攻擊的國家，而協約國是防守同盟。而且，英國和義大利簽署了有關地中海的協議。英國需要暢通的地中海道路，以容易接觸其非洲和印度殖民地。由於義大利大部分邊界被地中海包圍，她就付不起與英國為敵的代價。這也被認為是義大利改變立場的原因。

The Triple Alliance was a military alliance between Germany, Austria-Hungary, and Italy that lasted from 1882 until the start of World War I in 1914. Each member promised mutual support in the event of an attack by any two other great powers, or for Germany and Italy, an attack by France alone. In a supplementary declaration, Italy specified that her undertakings could not be regarded as being directed against the United Kingdom. Shortly after renewing the Alliance in June 1902, Italy secretly extended a similar guarantee to France.

Italy joined the German-Austrian Alliance to form the Triple Alliance partly in anger at the French seizure of Tunisia in 1881, which many Italians had seen as a potential colony. However, Italian public opinion remained unenthusiastic about their country's alignment with Austria-Hungary, a past enemy of Italian unification, and whose Italian-majority districts in the Trentino and Istria were seen as Italia irredenta ("unredeemed Italy").

In the years before World War I, many distinguished military analysts predicted that Italy would change sides. This prediction was strengthened by Italy's invasion and annexation of Tripoli, bringing it into conflict with the German-backed Ottoman Empire.

When Germany and Austria-Hungary found themselves at war in August 1914 with the rival Triple Entente of Britain, France, and the latter's ally, Russia, Italy pledged its support to the Central Powers, but subsequently entered the conflict on the side of the Entente against Austria-Hungary in May 1915 and Germany in August 1916.

Italy's ideas for maintaining the balance of power in Europe clearly gravitated towards major alliances, even if they were a passive member. Italy's reasoning for not siding with the Central Powers was that the Triple Alliance was a defensive alliance, but Germany and Austria-Hungary had taken the offensive. It is also thought that Britain and Italy had an agreement about the Mediterranean. Britain needed access to the Mediterranean, so that she could access her African and Indian empires easily. Because Italy is surrounded by the Mediterranean, it could not afford to fall out with Britain. This is thought to be another reason that Italy changed sides.