I'm afraid very few Japanese students visit this forum.
I recommend you to post your question at
Japanese students BBS. Your question will be welcomed.
Here you can raise new thread by clicking the link at left under part of this page.
And then in the next page, you can post your question right bottom part of this page.
There are some character encoding problem in your Japanese text in question 4), 6) and 11). Check the characters carefully after translation (by machine?),