He was always making diagrams of verbs and their inflections, and he looked for opportunities to show off his mastery of the pluperfect and future perfect tenses, his two favorites. 他总是把动词及其变化绘制成表，然后便寻找机会炫耀他的两个最爱——过去完成时和将来完成时。
If for no other reason than the use of pluperfect tense.
辩方律师使用了虚拟语气。
中文百科
过去完成时
过去完成时（英语：pluperfect tense，来自拉丁语 plus quam perfectum 更加完成），在英语中也叫做“past perfect”，是存在于多数印欧语言中一种完成性时态，用来指定在另一个过去行动之前就已经完成了的一个事件。
英语百科
Pluperfect 过去完成时
The pluperfect is a type of verb form, traditionally treated as one of the tenses of certain languages, used in referring to something that occurred earlier than the time being considered, when the time being considered is already in the past. The meaning of the pluperfect is equivalent to that of English verb forms such as "(we) had arrived" or "(they) had written".