A-A+
I have been for years troubling the pages of h
问题详情
I have been for years troubling the pages of historians, to find out what our fathers have done to the native Americans, but I must say, that my researches have ______ been to no effect.
A．therefore
B．hitherto
C．however
D．nevertheless请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：B
解析：该句意为：我花了几年的时间来阅读历史学家的书，为的是找到我们的祖先对美国印第安人做了什么事，但是我必须说到目前为止，我的研究还没有什么成效。therefore：因此；hitherto：至今；however：无论如何；nevertheless：仍然，不过。
