But I don't know if I think too much.为什么要把 if 改成whether?

But I don't know if I think too much.为什么要把 if 改成whether?
But I don't know if I think too much.为什么要把 if 改成whether?

But I don't know if I think too much.为什么要把 if 改成whether?
不用改为whether,if和whether都可以是“是否”的意思,都可以引导宾语从句.if要改为whether在下列几种场合：
1,当宾语从句有or not时；
2,引导主语从句;同位语从句和表语从句时；
3,做介词的宾语从句时.
4,与不定式连用时.
楼主的句子不在此列.