Had done的意思

"Had done" is a past perfect tense form of a verb, which is used to indicate that an action was completed before another past action or time. For example:

• By the time we arrived, the meeting had already started.
• She said she had finished her homework before she watched TV.
• I had done my best, but I still didn't win the competition.

In these examples, "had started," "had finished," and "had done" are all past perfect forms, indicating that the actions were completed before a specific past time or another past action.