If the only reading you ever do is the novel or magazine, the speed at which you read probably does not matter very much. But if you have to read a great deal for study, you will appreciate the benefits of being able to read more quickly. Here are some tips to help improve your reading speed. 

这是2021年新高考英语全国卷2的阅读理解七选五中的一段。请问句中的 at which 是引导定语从句吗？感觉结构有点奇怪。