题目

China has many special forms of traditional art, ______ sky lanterns, paper cutting and Chinese clay art.      A. such as     B. instead of   C. except for  D. because of 答案：A  抛物线过焦点F的直线l交抛物线于A．B两点，O为原点，若△AOB面积最小值为8。    （1）求P值    （2）过A点作抛物线的切线交y轴于N，则点M在一定直线上，试证明之。