If we give up the idea that higher levels are literally constructed out of lower level elements, as I think we must, then it becomes much more natural to consider even such abstract systems of representation as transformational structure (where each utterance is represented by the sequence of transformations by which it is derived from a terminal string of the phrase structure grammar) as constituting a linguistic level.

【结构分析】

1. If we give up the idea that higher levels are literally constructed out of lower level elements: 是条件从句。

2. it becomes much more natural to consider even such abstract systems of representation as transformational structure as constituting a linguistic level: 是主句。

3. 在主句中，to consider even such abstract systems of representation as transformational structure as constituting a linguistic level 为真实主语，it 为形式主语。

第一个as 跟such 搭配，即：such...as...像......一样的，如......一样的

such abstract systems of representation as transformational structure 意为：“抽象的表达系统如转换结构”。

第二个as 跟consider 搭配，即：consider...as...认为......是......

4. 括号内的部分：where引导定语从句修饰structure，by which = by the sequence

【注】以上文字似乎是论述“转换语法”的一些观点。