题干
The survey_________in our school last month shows that about 2 percent of the students are addicted to Internet games.
A：conducting
B：having been conducted
C：conducted
D：to be conducted
答案(点此获取答案解析）
C
，若椭圆上存
在点
，满足以椭圆短轴为直径的圆与线段
相切于线段