Nobody can remember what they hear or read without certain number of repetition. Others act smart in your class because they ALREADY have some background on the LEED subject, and because they have already read some related material before (preview). The key for you is to find the proper study method that fit your personality, start slow and incrementally, make sure you understand the information first, and then repeat them. After you repeat the information a few times, you WILL remember them.
“Another important strategy is to review the material in a timely manner. Some people say that the best time to review material is between 30 minutes and 16 hours (the 3016 rule) after you read it for the first time. So, if you review the material right after you read it for the first time, the review may not be helpful.
I have personally found this method extremely beneficial. The best way for me to memorize study materials is to review what I learn during the day again in the evening. This, of course, happens to fall within the timing range mentioned above.”
Quoted from page 8 of “LEED Green Associate Exam Guide,” Non-exclusive right of use granted.
Gang Chen, Author, Architect, LEED AP BD+C (http://GreenExamEducation.com/)