thatifwhether引導的賓語從句的區別

這三個連詞的區別是that連接陳述句，而whether或if連接沒有特殊疑問詞的疑問句。

如：I said，"He will come." 改成賓語從句是I said that he will come. 

而I asked，"Will he come?" 改成賓語從句則是I asked if/whether he would come.

因此that與if， whether不同。