随着智能手机的普及，微信就是时下流行的一款手机语音聊天软件，语音信息是利用手机通过一定频率的____ 进行传播的．手机屏幕上很容易沾上灰尘，原因是：____ 

如图1，在四边形ABCD中，AD∥BC，∠B=∠C=60°，P、Q同时从B出发，以每秒1单位长度分别沿B﹣A﹣D﹣C和B﹣C﹣D方向运动至相遇时停止，设运动时间为t（秒），△BPQ的面积为S（平方单位），S与t的函数图象如图2所示，则下列结论错误的个数（   ）

①当t=4秒时，S=4 $\sqrt{3}$ ②AD=4   

③当4≤t≤8时，S=2 $\sqrt{3}$ t       ④当t=9秒时，BP平分四边形ABCD的面积．

    Every weekend is important to the Franklin's family. During the week they don't have very much time together, but they spend a lot of time together on the weekend.

    Mr. Frankin works at the shoe store downtown during the week, but he doesn't work there on the weekend. Mrs. Franklin works at the city hospital during the week, but she doesn't work there on the weekend.

    Bobby and Sally Franklin go to the junior high school during the week, but they don't go there on the weekend.

    And the Franklin's dog Rover stays at home alone during the week, but he doesn't stay at home alone on the weekend.

三个连续整数中，n是最大的一个，这三个数的和为____