SAT语法真题求解!会的进!

题目

SAT语法真题求解!会的进!
Most of the books around this old house smell of mildew,and if you pick one up you will find that the spine has deteriorated and their covers have rotted.has deteriorated 改成什么?

答案

我认为 你的 答案错了has deteriorated 并不错.
正确答案 应该是 their covers have 错了.
应该是 its cover has
因为前面说的是 pick one up
是单数.