I asked her__if__ she was enjoying her dinner.为什么不能用whether

I asked her__if__ she was enjoying her dinner.为什么不能用whether I asked her whether she was enjoying her dinner 为什么用was enjo i asked her whether she was enjoying her dinner.我想知道,后面从句,必须 I asked her whether she was enjoying her dinner是否可以用if代替whet I asked her whether she had looked in despair ,i asked her,"are you enjoying your dinner?"改为间接引 I asked her whether she agreed请分析一下句子成分 I was with her in the kitchen enjoying cooking 为什么这的enjoy要加i i asked her what she cooked for dinner是什么从句吗? I asked her where she was going and what she was going to do Then he asked her whether she needed help dressing He asked her whether she needed help dressing句子成分