麻烦分析下句子结构~在线等

Question

The first time that the question “
What is at the bottom of the oceans?” had to be
answered with any commercial consequence was when the laying of a telegraphcable from Europe to America was proposed.

Answer 1

整体：
"The first time that the question “What is at the bottom of the oceans?” had to beanswered with any commercial consequence“这是整个大句子的主语
was是大句子的系动词
" when the laying of a telegraphcable from Europe to America was proposed."是表语
整个句子是主系表结构

再来分析大句子中间的从句
1、The first time that the question had to be answered with any commercial consequence
应该是定语从句。

"The first time”是先行词，
that是关系代词，
" the question had to be answered”是从句
“with any commercial consequence ”是with伴随结构。

2、when the laying of a telegraphcable from Europe to America was proposed.
应该是时间状语从句
the laying of a telegraphcable 是主语
was proposed是谓语，因为主语“海底电缆”是被埋在海底，所以是被动语态。

整个句子的翻译是这样的：
“海洋的底部都有什么”这个问题第一次从商业角度被回答，是在铺设从欧洲到美国的海底电缆这个项目被提出来的时候。（为了能让中文通顺，我在不影响句意的情况下，多加了几个词，希望你能理解~）
有什么问题可以继续追问