在空间中,过点作平面的垂线,垂足为,记.设是两个不同的平面,对空间任意一点,,恒有,则（　　）

A：平面与平面垂直

B：平面与平面所成的(锐)二面角为

C：平面与平面平行

D：平面____about the apple products(产品) from the USA. Now, there are m____of apple fans in China. Many of t____are teenagers. The price of apple products is very h____but people think they are b____modern and fashionable, as if they are from the future. It is said that there is a student who would like to s____his kidney（肾）to buy an i-phone. In fact, it is not n____for students to own the expensive mobile phones because even you can use the most common one to play games, chat on QQ with friends o____search on the Internet. The biggest use of a mobile phone is making c____and in most schools mobile phones are forbidden(禁止).