她 已经完成 报告，那时老板来了。 She had finished the report when the boss arrived.
他们 已经居住 在那里十年，然后搬走了。 They had lived there for ten years before moving.
我 还没有吃 晚餐，那时你打电话来。 I hadn't eaten dinner yet when you called.
我们已经熟悉了现在完成时（Present Perfect），它将过去的事件与现在联系起来。然而，当我们叙述一系列复杂的过去事件时，需要一种更精确的工具来区分它们的先后顺序。这就引入了过去完成时。过去完成时用于描述一个动作发生在过去某个特定时间点之前。这个特定时间点充当了我们的参考点。这种用法我们称之为双点定位法，即确定：1. 动作点 (P1)；2. 过去的参考点 (P2)。P1 必须发生在 P2 之前。其结构为：主语 + had + 过去分词 (V3)。 We are familiar with the Present Perfect, which connects a past event to the present. However, when narrating complex sequences of past events, we need a precise tool to differentiate their chronology. This introduces the Past Perfect Tense. The Past Perfect is used to describe an action that was completed before a specific point in the past. This specific time functions as our reference point. We call this usage Double-Point Positioning, where we establish: 1. The point of action (P1); and 2. The past reference point (P2). P1 must occur before P2. The structure is: Subject + had + Past Participle (V3).