在△ABC中，已知a=$\sqrt{2}$，b=2，B=45°，则角A=(       )．

“凑够一摄人就可以走了，和红绿灯无关”。一条“中国式过马路”的微博在全社会产生了强烈反响。

   据统计，2012年1至10月，我国平均每天2.6人死于闯红灯肇事，86人死于违反道路标志线肇事。2012年12月2日是首个“全国交通安全日”，中央文明办等部门围绕“遵守交通信号，安全文明出行”的主题，联合部署了相关活动。海拉尔区公安局开展了交通安全宣传教育活动，组织民警走上街头，走进学校和社区，以丰富多彩的形式，宣传普及道路交通安全法律法规，提高人们的交通安全意识。

据悉，你校学生会打算组织一批志愿者参与本次宣传教育活动，请你加入并完成如下任务：

    I was playing in my kitchen. My mom stood in front of me, hardly keeping the tears from spilling over. She told me that my little cousin had cancer. Hearing this, I went completely numb. How could this be happening? I had just seen her, and she was fine.

    These things didn't happen to our family, that's what my uncle said. It seemed like the world turned upside down; just last week my grandmother had passed away. I felt like I couldn't get my feet on solid ground.

    That's when my sister, Ella, came down the stairs with her long brown hair freshly washed. She sat next to me and smiled. Despite what was happening, everything would work out, her smile seemed to say.

    “Mom, do you think I could get my hair cut tomorrow?” Ella asked.

    “Sure,” Mom said, starting to wash the dishes.

    “I want to donate it to Locks of Love” Ella smiled.

    My mom stopped washing and turned to look at her. “Are you sure?” I noticed that Mom was holding back tears. This was a sacrifice(牺牲) for Ella. Her long hair was an important part of her.

    “Yeah, it's just hair. Eventually it will grow back.” She said.

    “All right,” Mom said quietly, smiling again.

    Ella gave up a part of herself for a while. She let a piece of herself go to someone else, someone she didn't know. That day she became my hero too.