用适当方法解下列方程：

城市热岛效应出现的主要原因是     （   ）

今年5月31日是第29个“世界无烟日”，主题是：拒绝烟草危害．为宣传这一主题，实验小组应一品牌香烟各半支的烟丝，分别加入50mL、40mL、30mL、20mL蒸馏水浸泡一天，取其浸出液进行了“烟草浸出液对水蚤心率的影响”的研究．实验结果见表．

阅读材料，完成任务。

    My uncle Jack is an interesting man. When he speaks, his mustache（胡子） always dances. It is so funny. He wears glasses and a funny hat.

    I don't like my boss（老板） at all. He is heavy with two small eyes. I think his glasses are too small for him.

— Look, the salesman（商人） is coming.

— Which one?

— The one with short black hair. He always takes his umbrella(雨伞) and suitcase(旅行箱). And his tie is very ugly.

— What are you doing, Lucy? Look at your pants. They are so dirty!

— I am doing some cleaning. Don't come here, Jane. Your beautiful skirt will be dirty.

如图，在线段AE同侧作两个等边三角形△ABC和△CDE（∠ACE＜120°），点P与点M分别是线段BE和AD的中点，则△CPM是（　　）

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