In general, how to improve reading comprehension in nonfiction books?
I am a high school sophomore, and I am strongly interested in history and religions, so I have the urge to read long and technical nonfiction books regarding them. (For example large textbooks about Roman history and such) But what always happens is that my eyes scan through the words without absorbing the meaning. I am able to comprehend in the beginning, yet I start to lose retention later on. My fluency in English is perhaps one reason. Please allow me to introduce my background first. I am an American of Chinese descent. Supposedly, English is my mother tongue, yet I went to China to study for eight or nine years and I came back. During this time period English was a skill that I neglected, so later I put in great effort to recover this. Recently I returned to the states and started high school. Currently, I am very skilled in writing, listening and speaking, yet reading seems to be the only problem.Here is my question. Is the reason for my poor reading comprehension a matter of fluency in language, or it is simply because the books that I read are too deep for a sophomore? If it is because of fluency, how can I solve this problem? This problem is really frustrating me since I do have a hunger for knowledge. The inability to read is truly vexing me.Thank you very much!