Hey lukey2,
We don't summarise in class, we answer all the questions in the textbook (Business Studies in Action). I actrually think just summarising is pretty good. I learn most things that way, because I tend to just copy the answers for the questions from the textbook without actually reading through it.
When summarising, I look at the syllabus and read through that particular dotpoint in two or three textbooks, look for what I believe is most correct and then just go from there. Any concepts I don't understand, I just go to school and ask my teacher.
You might think that your teacher is being lazy, but he/she might believe that summarising is the best method, and if you don't talk to him/her about it, he/she will continue to think that its a good method because noone is telling him/her otherwise. Also, I cannot stress the importance of asking your teacher for help. If you don't ask, they will just assume that you understand everything. And they know a lot more than you think.
Also, to help with short answer questions, I suggest Leading Edge Business Studies Workbook.
Hope that helps.