I am not sure if she is from Canada.还是I am not sure that she is from Canada.原题 is she from Canada?i'm not sure.合并为一句
问题描述：
I am not sure if she is from Canada.还是I am not sure that she is from Canada.
原题 is she from Canada?i'm not sure.合并为一句
答
that
答
用that
答
I am not sure if she is from Canada
答
I'm not sure if she is from Canada.
答
肯定是用if或者whether也行
答
前面那句
答
if.
答
I am not sure if she is from Canada.或者 I am not sure whether she is from Canada or not.
答
都可以，但表达意思略有不同。用if表示我不太确定她是不是来自加拿大，用that的话表示我不太确定她是来自加拿大的（对于她来自加拿大这件事情，我不确定，说不好）