人教版高中英语选择性必修第二册Unit1 Science and Scientists Period 3 课件（该课件内含音频文件）

whether在表语从句中表是否但不充当句子的成分。
1.What the doctor really doubts is whether my mother will recover from the serious disease soon.
2.The question is whether it is worth doing.
She asked me if /whether she could borrow these books .      
The question is if/whether we can rely on him.
在表语从句中, 表“是否” 时, 只能用“whether”不能用“if”。
what 在表语从句中充当主语、表语、宾语 表示什么，什么样子，或所…的（人或事）
1. The question is what caused the accident.              
2. That mountain is no longer what it used to be .
3. What he told you was what had been discussed at the meeting.