最关键的一点在于:on是介词，因此要加名词，代词和动名词， as soon as是连词，所以要加句子．因此在句子变化的情况下，是可以互换使用的． 比如： On hearing the news, he cried. He cried as soon as he heard the news.
可以换 On arriving home, I phoned my mother 。= As soon as I arrived home, I phoned my mother。 ( 一到家,我就给妈妈打了电话。) On hearing the bell, the students ran into the classroom。
=As soon as the they heard the bell, the students ran into the classroom。(一听到铃声,学生们就跑进教室。) On arriving at the shore,the girl struggled up the cliff towards the light she had seen。
= As soon as she arrived the shore, the girl struggled up the cliff towards the light she had seen。(一到达岸边, 姑娘就朝着她看到的灯光的方向挣扎着往峭壁上爬。
)。
不能
答：以wards结尾的词表示方向的还有:forwards朝前．．．backwards朝后，upwards朝上；downwards朝下详情>>
答：详情>>
