求英语高手，帮我分析下这个句子

Question

Perhaps the most important thing we learned is the idea of the teacher-as-reflective-practitioner will not happen simply because it is a good or even compelling idea
请帮我分析下这个句子，谢谢！
请问是主系表结构还是主谓宾结构？因为既出现了is又出现了happen，但是又不像从句，happen是谓语动词吗？或者说我理解的是，is后面的是一个表语从句，省略了that什么的？求英语高手解答！~
万分感谢！！~~

Answer 1

表语从句里面的that 不作成分，但不能省略 .
　The traditional view is ____ we sleep because our brain is “programmed” to make us do so. (2007上海)
　　A. when B. why C. whether D. that
　　[答案] D
　　[解析] 下划线处之后是包含一个原因状语从句的表语从句， 如果看不出它是充当整个句子结构的表语从句将难以把握整个句子的意思。因此， 应选择可引导名词性从句且不充当任何成分的that。

Answer 2

Perhaps the most important thing we learned 主语部分 we learned 定语从句

is 系动词
the idea of the teacher-as-reflective-practitioner will not happen simply because it is a good or even compelling idea 表语从句本回答被提问者和网友采纳

Answer 3

是主系表，应为is后面的成分是一个完整的句子，如你所说，省略了that