1. The debate over bilingual education centers on the issue of

whether the United States should foster the idea of single common

language, an idea, some believe, that has in the past been crucial

in binding diverse constituencies together.

(A) been crucial in binding diverse constituencies together

(B) been crucial as a binding together of diverse constituencies

(C) been crucial to bind together constituencies that are diverse

(D) become crucial in binding together diverse constituencies（A）

(E) become crucial to bind together constituencies that are diverse

这句子只有主语是debate，那谓语动词是什么？

an idea 以后的内容好像是都是 the idea of single common language 地

同位语，那就没有谓语了呀？？

另外，为什么选A，能说说其他每个选项的错误吗？谢谢！

sorry!

The debate over bilingual education centers on the issue of whether the United States should foster the idea of single common language, an idea, some believe, that has in the past been crucial in binding diverse constituencies together.

这句话的结构是the debate should foster the idea, an idea that has been.....

不同意楼上的 The debate centers on the issue（ of

whether the United States should foster（（ the idea of single common

language), an idea, some believe, that has in the past been crucial

in binding diverse constituencies together.））两个括号有交叉部分，用双括号表示区分。划线部分才是最主干成分。