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.
(E)less than one percent of homes had electricity, where lighting had still been
表示不到百分之一的家庭有电，应该是哪种表达？
electricity was in less than one percent of homes？there were less than one percent of homes with electricity？less than one percent of homes had electricity？
我为了与前文中的过去完成时态呼应，选了E，可这里为什么不能用过去完成时而一定要用一般过去时呢？