这又是一个关于语法和习惯用法的争议的问题,
尽管从语法来看
upon sth.being done
没有错,一般说法是
upon doing sth.
例：
Upon completing the assignment you will get the certificate
You will get the certificate upon completion of the assignment可是如果要使Upon completing theassignment变为被动语态，那be动词要不要省略，我只记得after和before的是不能省的，但不清楚upon按时态要说 upon the assignment being completed但一般人说 upon completing the assignment语言不仅是语法，也是习惯，俗语说，language is usage(即 language is what common usage makes it)比如“这本书一旦完成就要出版”，用upon，主语为书，怎么造The book will be published upon its completion （句中）Upon its completion the book will be published （句首）你还是没明白我的意思呢~~~~~upon its completion 如果改种说法，是upon beingcompleted 还是upon completed我明白你的意思，我是说不可说 upon being completed 或 upon completed人家笑你的。