Recently, I felt like I reached a very low point in life. My relationships weren't good, I wasn't enjoying my classes, and I felt like I had nothing to1.My life seemed to be full of endless homework, tests and loneliness. Nothing anyone said seemed2o me. I wasn't sure what to do about myself. All I wanted was to be happy again, but I didn't know who or what would3that.

    During these days, I had trouble sleeping. I had to take sleeping pills but still woke up in the midnight. I had no4but to tell my dad. He5the book The Secret. I immediately bought the e-book online and read the whole thing that night. I'm6quite a stubborn person, but the effect on my mood after finishing the book was7. Suddenly, I felt like life was beautiful again. I had never felt such a deep and quick8in my life before.

    In fact, the book's message was very simple—think positively(积极地).The book had many success stories about how people were able to9money, soul mates(心灵伙伴)and old friends back into their lives. I started learning to thank everything in my life like them. Little by little, I realized that The Secret could only work10I believed these people's success stories.

    Now I'm sure I can bring myself happiness.

阅读图文材料，完成下列要求。

    2013年9月3日，广西崇左市市长信箱收到一封网民来信：这几年，我市在大力发展桉树种植，虽然其适应性强，生长速度快，经济见效快，但危害更严重。种植桉树导致了地下水位下降、土地肥力下降、水质恶化、原有植被无法存活、水土流失加剧等问题，老百姓都说它是“抽水机”、“耗肥机”、“毒树”和“生态杀手”！希望政府能多为子孙后代考虑，好好管理一下吧。

市长回复：感谢您对我市发展的关注！就您反映的问题，现答复如下：专家研究表明，桉树没有毒性，其单位重量干物质合成所需水量远小于针叶林、黄檀、相思等树种，肥力消耗也小于玉米、咖啡、马占相思等农作物。我市桉树种植有如下误区：（1）每亩植株多在300颗以上（推荐每亩100颗左右）；（2）砍伐周期3~4年（巴西约7~8年）；（3）大量使用除草剂去除林下“杂灌木”；（4）“炼山”；砍伐后防火烧山。所以，我市一些地方出现的生态环境问题并不是桉树之过，通过合理种植是可以避免的。另外，我市贫困地区较多，利用桉树发展相关产业（如木材加工、造纸等），对我市扶贫工作开展有重要意义。

用反证法证明命题：“三角形的内角中至少有一个不大于60°”时，假设正确的是(   )

若你发现有个下水道井盖丢了，你会怎么做？