as soon as意为“一……就……”，引导时间状语从句。
Please call back as soon as you arrive school.
I’ll write to you as soon as I get there.
As soon as I went in, Tom cried out with pleasure.
【拓展】as soon as 引导的时间状语从句前后时态搭配：
SHe will come to my home as soon as she gets to tianjin. 她一到天津就来我家。
SHe took out her English book as soon as she sat down. 她一坐下，就拿出她的英语书。