请教PREP1 81

81.
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In the major cities of industrialized countries at the end of the nineteenth century, important public places such as theaters, restaurants, shops, and banks had installed electric lighting, but electricity was in less than one percent of homes, where lighting was still provided mainly by candles or gas.

(A) electricity was in less than one percent of homes, where lighting was still

(B) electricity was in less than one percent of homes and lighting still

(C) there were less than one percent of homes with electricity, where lighting was still being

(D) there was less than one percent of homes that had electricity, having lighting that was still

(E) less than one percent of homes had electricity, where lighting had still been

这道题目的答案是A，我想问一下one percent of homes这种的主语谓语是单数还是复数呢？我记得上新东方的时候老师说one percent都用单数，可是白勇的语法里面说要看后面的名词的单复数，应该怎么判断啊？谢谢大家。

percent的用法是a percent of+单数，就是单数

                            +复数，就是复数