如图，等腰三角形ABC中，AB=AC=5cm，BC=6cm，动点P从点A出发，沿路线A﹣B﹣C匀速运动，速度为1cm/s，运动到C点停止，设运动时间为t（s），△APC的面积为y（cm²）．

    Here are the messages Lois took for people in her office.

Message For Mr. Ford     Date (日期) July 2nd

Time 12:10 p.m.

（）Urgent(紧急的)  (√)Not urgent

（）Don't call back   (√) Call back at 545-1245

Message: Mr. Gomez of Big World Bank called. He wants to meet with you tomorrow.

Message For Ms. Lee     Date July 2nd

Time 12:15 p.m.

(√)Urgent          （）Not urgent

（）Don' t call back   (√) Call back at 267-3722

Message: Mr. Hiram needs to cancel (取消) today's meeting. He wants to have it at 9:00 a.m. tomorrow.

Message For Mr. Green   Date July 2nd

Time 12:25 p.m.

（）Urgent          (√)Not urgent

(√)Don't call back   （）Call back at 554-2781

Message: Dr. Jee's office called to remind (提醒) about the appointment (预约) on Friday.

Message For Ms. Brown   Date July 2nd

Time 12:40 p.m.

(√)Urgent         （）Not urgent

(√)Don't call back   （）Call back at 681-7561

Message: Your daughter's school Called. Susie doesn't feel well. Please pick her up.

如图所示，物体从斜面上A点由静止开始下滑，第一次经光滑斜面AB滑到底端时间为t₁；第二次经光滑斜面ACD下滑，滑到底端时间为t₂．已知AC+CD=AB，在各斜面的等高处物体的速率相等，试判断（　　）

社会主义民主政治的本质要求是（   ）