请帮忙分析一下这个句子的各个部分之间的关系

题目

请帮忙分析一下这个句子的各个部分之间的关系
American schools,both public and private,consist of 12 years of grades- basically 8 years of eelementary school and 4 years of secondary of high school ,although grades 7 and 8,of 7,8 and 9 may be housed together in a middle school of junior high school.

答案

American schools主语
both public and private对主语的限定和补充,同位语
consist of谓语
12 years of grades- basically 8 years of eelementary school and 4 years of secondary of high school 宾语
although连词连接从句
grades 7 and 8, of 7,8 and 9从句主语
may be housed从句谓语（被动）
together in a middle school of junior high school从句状语.