完形填空
   Do you have the ability to live cheaply? Now here's a true story of an American girl, Sarah. After Sarah left university, 1 began to live in New York City on her own. She 2 a job in a publishing house, but the salary was less than $30，000 a year. Her parents thought her life would be hard, but Sarah could live on her 3and still saved $5,000 in a year. How was that 4 in one of the most expensive cities in the world?
   Cheap living always starts with keeping the big cost small．For most people, that means housing. So Sarah chose to 5 a flat with three other friends. Her next biggest cost was 6. When she ate out, she went to cheap restaurants.7she bought a $9.99 whole chicken at a local restaurant. She then 8the chicken bones(骨头)home and made soup out of them. Nowadays young people often 9 a lot of money on entertainment(娱乐). But Sarah said, "I enjoy walking 10 in New York City. I love going to museums and parks." Did Sarah feel poor by cheap living? Not really. She 11managed to take two trips, one to the Netherlands, the other to Portland.“Don’t think of saving money as something 12. It's a kind of game,” said Sarah.

Edison is a famous ____(发明家) all over the world.

α-丙氨酸是组成人体蛋白质的氨基酸之一，其分子结构如图所示。（注：“ ”表示氮原子；“ ”表示碳原子；“ ”表示氧原子；“ ”表示氢原子，“-”表示原子之间相互连接。）

则α-丙氨酸中含有____种元素，其中碳、氧2种元素质量比为____，其相对分子质量是____。

某研究性学习小组利用气垫导轨验证机械能守恒定律，实验装置如图甲所示，当气垫导轨左侧工作时导轨两侧喷出的气体使滑块悬浮在导轨上方，滑块运动时与导轨间的阻力可忽略不计．在气垫导轨上相隔一定距离L的两处安装两个光电传感器A、B，滑块P上固定一遮光条，若光线被遮光条遮挡，光电传感器会输出高电压，两光电传感器采集数据后与计算机相连．滑块在细线的牵引下向左加速运动，遮光条经过光电传感器A、B时，通过计算机可以得到如图乙所示的电压U随时间t变化的图线．