下题在prep08笔记里面说staging是一个持续动作，而不是在1911时完成的动作
Except for a concert performance that the composer himself staged in 1911, Scott Joplin’s ragtime opera＂Tree monisha＂was not produced until 1972，sixty-one years after its completion．
(B) Except for a concert performance with the composer himself staging it
---staging suggests ongoing action rather than action completed in 1911．