题目

阅读理解When we first gave our daughters (then 13 and 15 years old) cell phones for emergencies, we made them sign an agreement in which we strictly ruled where and when they could use their phones and even we could check their every text message. However, in less than a year, we lost control of the situation.There is a terrible reality that almost every teenager sends between 50 to 100 messages a day - some as many as 300, and 70% of teenagers admit hiding their online behavior from parents. According to a study, teenagers need as much sleep or more than they get as children - that's betw设命题p：函数y＝sin 2x的最小正周期为；命题q：函数y＝cos x的图象关于直线x＝对称，则下列判断正确的是(　　)．A．p为真B．綈q为假C．p∧q为假D．p∨q为真