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

答案选A

但很明显A中缺少that

C为什么不对呢?

谢谢

哪里少that？

C中的过去完成时没有依据。

记得有一说once 后面只用现在完成时.

我有点不明白:这里的this body of work 是指什么?  understand sth/sb to do好象有点怪.  为什么不是scholars now understand that this body of work consists of... 呢?

有没有人知道?  Thanks.

once不会只用于现在完成时态吧

我觉得很多一般过去的也经常用

understand A to be B的句式是存在的正确的我查了字典大概就是consider,regard之类的意思

this body of work我觉得就是指Native American literatures