如图，已知直线AB，CD被直线AC所截，AB∥CD，E是平面内任意一点（点E不在直线AB、CD、AC上），设∠BAE=α，∠DCE=β．下列各式：①α+β，②α﹣β，③180°﹣α﹣β，，④360°﹣α﹣β，∠AEC的度数可能是（   ）

如图，正方形ABCD的边长为5，E是AB上一点，且BE：AE=1：4，若P是对角线AC上一动点，则PB+PE的最小值是____．（结果保留根号）

温家宝总理指出，“我深知国之命在人心，解决人民的怨气，实现人民的愿望，就必须创造条件，让人民批评和监督政府。”这是因为(　 　)
①监督政府是政府赋予公民的权利
②监督政府有利于克服官僚主义，消除腐败根源
③我国是人民当家作主的社会主义国家
④政府接受监督是政府坚持依法行政，做好工作的必要保证

阅读理解
    Tom lives in the UK. His friend Jack is in Dubai. He will go to see his friend. First he needs to go to London to take the plane.
    On Friday morning, Tom takes a bus to the train station. It takes Tom about 30 minutes to get there. Tom gets on the train at about 10 o'clock：The train leaves at 10：15. The train trip to London takes three hours. At lunchtime Tom gets to London. Tom eats a hamburger for lunch. Then he goes to the airport(机场)by subway. After about one hour,Tom gets to the airport. Tom gets on the plane at 8 o'clock in the evening. The trip takes a long time. Tom is tired(疲倦的)after a busy day. So he goes to sleep(睡觉). On Saturday morning, Tom gets to Dubai. He is very happy, because he will have a great time with his friend.

如表是某研究小组探究影响反应速率部分因素的相关实验数据．

实验序号	H2O2溶 液浓度%	H2O2溶液体积/mL	温度℃	MnO2的用量/g	收集氧气的体积/mL	反应所需 的时间/s
①	5	1	20	0.1	4	16.75
②	15	1	20	0.1	4	6.04
③	30	5	35		2	49.21
④	30	5	55		2	10.76