There is a new park near Andy's home. It's fine today. Andy and his family are in the park now. On their left, there is a café. On the right, there is a big lake. There are many flowers and trees around the lake. There's a small hill behind the lake. Near the lake, there are two signs（标记）. One says, "Don't swim in the lake."But you can go boating on the lake. There is a beautiful garden in the middle of the park. There are green grass and beautiful flowers in it. There are some small shops between the lake and garden. The park is so nice. Andy and his family like it very much.

影响气候的主要因素有____、____和地形等。

 人类是生活离不开水，某生活污水主要含有碎菜叶、碎塑料薄膜、泥沙、氯化钠和碳酸钠等物质．现欲将其经去渣处理后作为清洗厕所的用水．请问：

（1）捡掉污水中的碎菜叶、碎塑料薄膜等较大的固体后，可对污水进行____操作除去其中捡不掉的固体物质；把生活污水进行处理在利用的目的是____；

（2）①试剂A的化学式是　____ 　，试剂A加入过量的作用是____；

②写出步骤Ⅱ所发生反应的化学方程式　____  ；如果步骤Ⅰ先加入试剂B，步骤Ⅱ加入过量试剂A，也能达到检验氯化钠的目的，理由是____．