The most important river is the River of （）

填空题Natural gas was discovered in Britain in the（）

填空题The “Backbone of England” refers to the （）

填空题The highest mountain in Britain is（）

填空题The name United Kingdom of Great Britain and Ireland was replaced by the present name after the 26 counties of Ireland obtained autonomy in （）

填空题（）is composed of six Irish counties that elected to remain in the union with Great Britain.