动名词的逻辑主语到底用主格还是所有格

一般情况，动名词的逻辑主语用名词的通格或所有格、代词的宾格或所有 格。请看：

The wonder of the electronic computer lies in _____ in doing complicated calculations.

A. it being very quick and accurate B. its being very quick and accurate

C. it is very quick and accurate D. it was very quick and accurate

分析：按传统的语法，动名词的逻辑主语可以是名词的通格或所有格、代词的宾格或所有格。但现在一般都用代词的所有格作逻辑主语，美国英语中尤其如此。所以，最好

选B。这个语法点也是TOEFL常考的考点之一。请看下面两道含有代词作逻辑主语的最近的TOEFL题：

（1）With ____ her to this, she will have no difficulty persuading them to accept her plan.

A. I help B. my helping C. me helping D. mine helping

正确答案是B，而不是C。逻辑主语用代词所有格。

（2）改错题：Because they were unaware of his interest in the building, they did not understand why he felt so bad about it being pulled down.

应该改为: its being pulled down。逻辑主语用代词所有格。