Ungrammatical. The statement should have been; "Mother made sandwiches for both of us."
They are all the same because they are in the same area
There was not enough trained soldiers.
The alliance system caused the World War I to escalate from a regional conflict into a global war. Two major alliances existed in Europe prior to World War I. The Triple Alliance included Germany, Austria-Hungary, and Italy, while the Triple Entente included the Soviet Union, Britain, and France.