[求助]ttGWD-11-17

Q17:

Scholars who once thought Native American literatures
were solely oral narratives recorded by missionaries or anthropologists now
understand this body of work to consist of both oral literatures and the
written works of Native American authors, who have been publishing since 1772.

1. Scholars
        who once thought Native American literatures were solely oral narratives
2. Scholars
        thinking of Native American literatures once solely as oral narratives,
        and
3. Scholars
        who once had thought of Native American literatures solely as oral
        narratives and
4. Native
        American literatures, which some scholars once thought were solely oral
        narratives
5. Native
        American literatures, which some scholars once, thinking they were solely
        oral narratives

  
Answer: A

句子的主语应该是Scholars， 如果选D,句子的主干就变成Native American literatures now understand this body of work to consist of both oral literatures and the written works of Native American authors.明显不通。

而A的主干是：Scholars now understand this body of work to consist of both oral literatures and the written works of Native American authors.正确明白。