2.Basic to any understanding of Canada in the 20 years after the Second World War is the country’s impressive population growth．
(倒裝結構Basic to any understanding…is…)
要理解二戰(zhàn)之后20年中的加拿大，就必須了解該國驚人的人口增長。
分句1：Basic to any understanding of Canada in the 20 years after the Second World War
分句2：is
分句3：the country’s impressive population growth
分句1，2，3共同構成倒裝句，正常的語序應該是3，2，1，即：該句的正常語序是The country’s impressive population growth is basic to any understanding of Canada in the 20 years after the Second World War．
本句是一個簡單句，只不過使用了倒裝，謂語動詞是is.