my summary of Object-Oriented Programming concepts

Until to this week, we have learnt a lot about object-orientend design. I think I have had a good command of most of what the instructor taught in the class and the lad exercise, but I got a very very low mark for my assignment1, which surprised me deeply. Because I got almost full marks in my lab exercises and 90s in midterm test, which let me think that the object-orientend design is not difficult. However, when I used what I learned to design a real object like the game in assignment1, I found it was totally different from the test or lab. For each part, I can deal with the class easily and successfully with the description from handout. So, I just need pay attention to one specific function or method.

As for a object design, I do not have a clear thought about what should I do. According to some paragraphs of words, I need to find what kinds of classes I need to design and what methods I will use in every class. Most importantly, the codes I write should meet the requirement. I always can not decide what should be written in general class and what should be added to specific class. After reading the comments of my assignment,  I still feel confused about object-orientend design. In my opinion, there is few things can be done in general class because of various different kinds of object. Besides this, the function of game view confuses me very much. 

So, I still have a lot of questions about this topic even though I can run my game successfully. Should I drop?...