11. Yet, even if America’s trash output continues to rise as it has done in the past, and even if the American population doubles by 2100, all the rubbish America produces through the entire 21st century will still take up only one-12,000th of the area of the entire United States.(剑5, Test 1 passage 3)

　　分析：本句的主句为“all the rubbish America produces through the entire 21st century will still take up only one-12,000th of the area of the entire United States.”;其中“America produces”为定语从句，作all the rubbish的定语，关系词在定语从句中作宾语，被省掉;“even if America’s trash output continues to rise as it has done in the past,”和“even if the American population doubles by 2100”两个从句并列，皆为even if引导的让步状语从句。