全部

1·A notional figure of cost helps in determining production costs; speculative knowledge.

概念上的成本数字有助于决定生产成本；理论知识。

2·You can sometimes predict complexity based on speculative knowledge of the problem domain, but writing code creates new constraints and opportunities that are virtually impossible to predict.

有时候可以根据问题域的理论知识预测复杂性，但是在编写代码时，又会产生新的约束和机会，这些实际上是无法预测的。

3·Learn relevant mechanism knowledge and master plenty of speculative knowledge, which will help to analyze the mechanism and provide strong theoretical basis for the failure cause of control choke.

学习相关机理研究，掌握大量的理论知识，指导论文的机理分析，为找出油嘴的失效原因提供有力的理论依据。