语法总结
as soon as 引导时间从句
As soon as this was done 表示“这件事一做完就……”，从句动作先发生。
相似句：
- As soon as he arrived, we started.
- Call me as soon as you get home.
过去完成时表示更早动作
a stream had formed 说明小溪在孩子们发现它之前已经形成。
相似句：
- The road had flooded before we arrived.
- She had gone to bed when I called.