Thus, an ongoing strategy of deterrence resulted in which it was perceived as necessary to maintain a large deployment of weapons in order to create the threat of retaliation for the enemy.

1. 黑体部分是定语从句，先行词是句子主语 strategy 。
2. 这属于分隔式定语从句，因定语从句太长，为照顾句子匀称而后置，结果被谓语动词 resulted 分隔。resulted 跟 in 没有关系，不是“导致”。
3. which 指代 strategy，in which 意为“在这项威慑战略中”。
4. it was perceived as necessary to maintain a large deployment of weapons in order to create the threat of retaliation for the enemy 中，it 是形式主语，不定式to maintain a large deployment of weapons in order to create the threat of retaliation for the enemy 是真正主语。这是 perceive + 宾语 + as + adj. 结构（认为宾语怎么样），as...为宾补，被动语态是为主补。it was perceived as necessary  （it 指代不定式）被认为是必要的，人们认为是必要的。

5. 句末应为句号，问号没道理。

【翻译】因此，一项持续的威慑战略产生了，（在此战略中）人们认为有必要维持大规模的武器部署，以便对敌人造成报复的威胁。

先行词与定语从句被谓语分隔举例：

先行词是句子的主语，因定语从句较长，主句谓语较短，为使句子结构平衡，常将定语从句移至谓语之后。

The professor entered the hall who had just presented several lectures.刚刚做完几场报告的教授进了大厅。

The days are gone when we Chinese were bullied by the invaders. 我们中国人受侵略者欺负的日子一去不复返了。