5.I’m not sure___ he will come back home tomorrow or not.A.if B.what C.whether D.where
问题描述：
5.I’m not sure___ he will come back home tomorrow or not.A.if B.what C.whether D.where
答
选c
whether ...or not 是个固定搭配.意思是会.
常用于否定句和疑问句中.