i choose to study,so my opportunity cost is 6A friendship(等價交換).i am glad for receive a D- log book.
miss kwong said again and again to me.mr lau said again and again to me every day.even f.7 students say again and again to me,i need to pay much more effort and do a better piece of work to them.class position:10/29,if still remains this position,must died.........