No one knew ________.
A. she will comeB. if she would come
C. if she would come or notD. whether she will come or not
问题补充：
资料上面的答案是C,是《三·二》,应该算权威吧!
答：C/B
译：没人知道她是不是会来.
析：引导动词的宾语从句时,可以用if代替whether,但要注意,后直接跟or not 时,只能用whether, 不能用if or not.
正：No one knew if/whether she would come or not.
正：No one knew whether or not she would come.
误：No one knew if or not she would come.
主过从过,答案D的从句时态应用would come, 故排除D,同理排除A
但B也是正确的.
本题确实设计有误.
我估计原作者本来的“正确”答案是B.一般人以为：if 后不能跟or not(引导宾语从句）,其实这种说法不准确.确切地说法是：if后不能直接跟or not.

PS: 参考一下大多数人的回答,就知道确实很多人,（包括我以前）有这样的误if后不能跟or not.

权威词典例句《7in1》
if
《LE》
2. used to mention a fact, situation, or event that someone asks about, or is not certain about:I’m not sure if this is the right road or not.
《OL》
4.
used after ask, know, find out, wonder, etc. to introduce one of two or more possibilities
SYN whether:
I wonder if I should wear a coat or not.