Short answers, pulled from the story.
The principal Allied powers during World War II included the United Kingdom, the United States, the Soviet Union, and China. These four nations formed the Big Four and served as the core leadership for the Grand Alliance that defeated the Axis powers.
Representatives from the United States, the United Kingdom, the Soviet Union, and China signed the Declaration by United Nations on the 1st of January 1942. Twenty-six original signatories joined this declaration to commit to fighting together until victory was achieved.
Britain recognized Charles de Gaulle as the leader of Free French forces in opposition to the collaborationist Vichy government. The Free French were not officially recognized as a government-in-exile until 1944 despite their early formation.
India served as an important supply base for Commonwealth, American, and Chinese forces while producing approximately £286.5 million worth of military equipment. By 1945 the Indian army numbered 2.5 million people making it the largest volunteer army in history.
The Yalta Conference held in February 1945 brought together Churchill, Roosevelt, and Stalin to agree on zones of occupation for Germany and plans for the United Nations organization. This summit occurred after the Tehran Conference where they decided on a full-scale offensive in France for mid-1944.