你好这位朋友，加拿大的大平原地带主要横跨三个省份，合称为Canadian Prairies。我在Wikipedia和其他网站上帮你找了相关资料，并进行了简要的修改和整合成一篇简介如下。最后的一张里标明了大平原的在地图上的涵盖地域范围。
????The Canadian Prairies is a region in western Canada, which may correspond to several different definitions, natural or political. Notably, the Prairie provinces or simply the Prairies comprise the provinces of Alberta, Saskatchewan, and Manitoba, as they are partially covered by prairie (grasslands). In a more restricted sense, the term may also refer only to the areas of those provinces covered by prairie. Prairie also covers portions of northeastern British Columbia, though that province is typically not included in the region in a political sense.
The word prairie usually refers to a type of grassland, and true prairies occur only in the southern reaches of Alberta and Saskatchewan. Contrasted to this are other biomes such as the boreal forest taking up the majority of the Prairie Provinces, or the aspen parkland.
????However "the prairies" may also refer to all of the Interior Plains region within Canada, in contrast with the Rocky Mountains and Canadian Shield, and is a continuation of the Great Plains region of the United States.
????It may also refer to all of the farmland in the provinces of Alberta, Saskatchewan, and Manitoba, a definition based on human use, which includes all of the aspen parkland biome.
According to the K?ppen climate classification the Canadian prairies generally experience dry semi-arid climates (K?ppen Bsk) in the brown soil regions, and somewhat dry Humid Continental climates (K?ppen Dfb) in the outer dark brown and black soil areas. The Canadian prairies typically experience about 12 to 15 inches (300 to 380 mm) of annual precipitation in the semi-arid areas while they experience 16 to 20 inches (410 to 510 mm) in the continental regions. Manitoba is the most humid of the three prairie provinces.