81　at+名词或on+动名词→as soon as/when+句子

◎ 这两种结构可以转换，但要注意as soon as 后的句子时态。

比较

At the news，she burst out laughing. 她一听到那个消息就大笑起来。

As soon as she heard the news，she burst out laughing.

他一到达车站就直接进了候车室。

On arriving at the station，he went directly into the waiting room.

As soon as/when he arrived at the station，he went directly into the waiting room.