Oliver enters World War I and becomes sick during his tour.

Germany entered World War I in the first days of August 1914.

European powers had entered World War I in the beginning of August.

In 1917, Cuba entered World War I on the side of the allies.

Ten years later, he was recalled to military service when Italy entered World War I.

Canada entered World War I on 4 August 1914.

The United States did not have many machine guns when it entered World War I, and most were old technology.

When the United States entered World War I in 1917, he was opposed to joining.

When Italy entered World War I, the need for more military pistols increased dramatically.

Congress established a new system of veterans benefits when the United States entered World War I in 1917.