题目

下面图表是你们班级同学初高中阶段上网情况的调查对比，请你描述图表的变化并分析原因。注意：1）写作词数应为80左右；2）请按要求在答题的相应位置作答。 答案：To further understand the differences of online activities in junior high and in senior high, a survey was carried out in our class recently. The result is very interesting. 60% of my classmates played online games a year ago when in junior high, while only 20% do that now. There is little difference between the percentage of chatting, which is about 28% now, almost the same as a year ago. However下列函数的图象，一定经过原点的是（ ）A．B．y=5x2-3C．y=x2-1D．y=-3x+7