设男生人数为7，则女生人数为10，全年级人数为7+10=17，
7÷17=717．
故答案为：717．
—Will you join us in playing cards?
—Thank you, but ________ at the moment. [ ]
A. I'd like to
B. I'm afraid so
C. I'd rather not
D. I'd better not to
水泥粉磨系统流程？
