each other 和 one another 只能作宾语。如:
Susan and Robert kissed each other passionately. (kissed 的宾语是each other )
The girls looked at each other. (looked at 的宾语是 each other)
They seem to love one another very much.(love 的宾语是 one another)
The streets are all at right angles to one another.(介词 to 的宾语是 one another)
(以上例句摘自《朗文当代高级英语辞典》第六版)