核心问题
He has a lot of books, everyone of which are read through and marked from front to back. A B C D
给的答案要求将 are 改为 is。这无疑是正确的。但我认为试题本身有错误: everyone 应改为 every one。不知您是否同意我的看法。
词典解答
我完全同意你的看法。F. T. Wood 在 Current English Usage 中明确指出：“The compound everyone can be used only to refer to people. For things, two words (every one) are necessary (复合词 everyone 只能用于指人, 指物时, 必须使用两个词 every one):
She bought a dozen eggs, and every one was bad."
(参见 everyone/every one )