英文as soon as與upon用法(Usage of as soon as and upon in English)

as soon as為引導時間副詞子句的連接詞，意思為｢一…就…｣，連接幾乎同時發生的兩個動作
As soon as+S+V, S +V=S+V as soon as S+V(句子中兩個S主詞不一定要相同)，和as soon as意思相同的詞為once~及on/upon~，但on/upon~用法稍有不同
Upon/on+Ving..., S+V 由於upon引導的子句省略了主詞，所以只能用在主要子句和副詞子句為同一個主詞的情形
As soon as I got home, Tom called me.=Tom called me as soon as I got home.(我一到家時，Tom打電話給我)。
=Once  I got home, Tom called me.
As soon as he finishes the homework, he will play basketball with us.(一旦他做完功課後，他就會和我們一起打籃球)
=Once   he finishes the homework, he will play basketball with us.
=Upon/On finishing the homework, he will play basketball with us.

as soon as在主要子句為未來事實，從屬子句的時態需要用現在式
As soon as he finishes the homework, he will play basketball with us.

參見(See also)
副詞子句(adverb clause)
as soon as與upon用法(Usage of as soon as and upon)

as soon as與as long as用法(Usage of as soon as and as long as)

not until用法(Usage of not until)

so that用法(Usage of so that)

as result of/result in用法(Usage of as result of/result)

because/because of用法(Usage of because/because of)