原句:There must be few questions on which responsible opinion is so utterly divided as on that of how much sleep we ought to have.主要是对这个as on that of 有点懵,不太理解。
动词ing形式作状语,可以看作状语从句吗,该怎么理解呢?比如Seeing a note on the ground, the stranger picked it up.实际上应为When he saw a note on the ground, the stranger picked it up.谢谢老师解答