# 现在完成时 表示动作发生在过去，已经完成，但是对现在造成了影响或后果，动作可能还会持续。 可使用的时间状语为：`already已经 yet还` 形式为：have + 动词过去分词 ``` They have already arrived in Shanghai. She has played soccer for 3 hours. She hasn't finished the homework yet. ``` # 过去完成时 表示句中的动作发生在过去之前，即过去的过去，已经完成，对过去造成了一定的影响或后果。 形式为：had(have的过去式) + 动词过去分词 ``` They had arrived in Shanghai. She had played soccer for 3 hours. They hadn't finished the work yet. ```