如果不是因為句子太長, 我通常是會這樣寫. 但現在這樣子實在很不順口.

我會寫:

There is an unresolved controversy as to who really wrote the Elizabethan plays that are commonly credited to William Shakespeare.

我沒有文法基礎, 這純粹只是個人在國外住了20年的習慣用法.

其實把WHO當主詞看就解釋得了
I don't know who broke the glass.
你一直把who當補語看，當然想不出來了
誰是作者？作者是誰？－＞都可以寫成Who is the author?
但是在名詞子句裡，要先確認誰是主詞，再考慮動詞的位置
以上

理論上是可以的, 但要標點符號要注意, 如下:
There is an unresolved controversy as to who the real author of the Elizabethan plays -- commonly credited to William Shakespeare -- is.

其中的 "--" 是這樣打沒錯, 但是通常 Word 會在你按下第二個 space 之後打接下來的字時自動幫你改格式, 列印出來看起來就會像這樣:
There is an unresolved controversy as to who the real author of the Elizabethan plays ─ commonly credited to William Shakespeare ─ is.

如果是口述的話, 停頓和語調要有所區分才能讓人容易馬上聽懂意思, 否則我是覺得 "There is an unresolved controversy as to who is the real author of the Elizabethan plays commonly credited to William Shakespeare." 比較易懂

以上, 歡迎指教或補充

沒有前後文，有些東西很難討論....小弟人文素養太低....sorry

可以確定的是
『Elizabethan』在這裡是指『依莉莎白歌劇院』，
而所謂『Elizabethan plays』已經變成一個專有名詞
...plays在這裡不是動詞

因為
也可以理解成另外一個意思
如果立論已經相信William Shakespeare是個筆名，那背後的寫手的真名是？
因為他用credited to,而不是by