有一读者问： 高中课本有这样一句话：
(1)He walks to where she is sitting.
书上的解释是： 这里之所以用介词to是因为where从句在此起一名词的作用，这种解释正确吗？
完全正确。在语法中这种从句叫做名词性从句，可以用作主语、表语、宾语等。where从句在此用作介词to的宾语。用作介词宾语的从句不乏其例，再如：
(2)I'm sorry for what I said .
(3)We have no information as to when they will come .
(4)He wheeled to where she sat .
(5)She was surprised at how quickly she adapted to living alone .
(6)I'm concerned about whether he has signed the contract .
(7)She had no idea as to why she thought of him suddenly . （as to可省去）
(8)I shall take note of whom copies are to be sent to . （take note of常被看作一短语动词）
请注意上述这类宾语从句多由疑问词开首。
