1. 过去完成时

过去某个时间为止已经完成的动作，had +过去分词

时间状语：by last week, by the end of last week

Just as I got to school gate, I realized I had left my book in the café.

1. 过去完成时

过去某个时间为止已经完成的动作，had +过去分词

时间状语：by last week, by the end of last week

Just as I got to school gate, I realized I had left my book in the café.