# 現在完成時 表示動作發生在過去，已經完成，但是對現在造成了影響或后果，動作可能還會持續。 可使用的時間狀語為：`already已經 yet還` 形式為：have + 動詞過去分詞 ``` They have already arrived in Shanghai. She has played soccer for 3 hours. She hasn't finished the homework yet. ``` # 過去完成時 表示句中的動作發生在過去之前，即過去的過去，已經完成，對過去造成了一定的影響或后果。 形式為：had(have的過去式) + 動詞過去分詞 ``` They had arrived in Shanghai. She had played soccer for 3 hours. They hadn't finished the work yet. ```