阅读短文，回答下列问题

    One day a poor man was cutting a big piece of wood (木头) near a river. Suddenly his old axe (斧子) fell into the water. He felt very sad because he lost his only axe. Then all at once a beautiful fairy (仙女) came out and asked the man what was the matter.

    "I have lost my axe." he said, "It fell into the water when I was cutting the wood."

    The fairy showed him a gold axe and asked, "Is that yours?"

    "No." said the man.

    The fairy then showed him a silver (银) axe and asked again, "Is this yours?"

    "No." again answered the man.

    Then she showed  him the old axe.

    "Yes, that is mine." called out the happy man.

    "I know it well enough." said the fairy, "I only wanted to see if you would tell me the truth, and now I'll give you the gold axe and the silver axe besides (包括)  your own one."

如图，先填空后证明．

已知：∠1+∠2=180°，求证：a∥b．

证明：∵∠1=∠3____

∠1+∠2=180°____

∴∠3+∠2=180°____ 

∴a∥b____

请你再写出另一种证明方法．

2016年3月份以来，全国许多省市拉开了新一轮的村委会换届选举序幕。据此完成下面小题。

□○□＝□（朵）

2015年1月，一场前所未有的雾霾笼罩我国中东部的大部分地区，生活在其中，无人能够自强不“吸”。为此，网友们积极互动，倡议从“少开一天车”、“少放一个鞭炮”"开始，以自己的实际行动净化我们的天空，这一做法的哲学依据是（   ）。