面对中国当时财力支持不足、基础工业薄弱和专业人才匮乏等困境，航天工作者根据实际情况和中央的战略部署，提出由探空火箭研制起步的方略，摸索出实践经验后再向大型运载火箭进军，最终把卫星送上天。体现了（   ）

如图，Rt△APC的顶点A，P在反比例函数y＝$\frac{1}{x}$的图象上，已知P的坐标为（1，1），tanA=$\frac{1}{n}$（n≥2的自然数）；当n=2，3，4…2010时，A的横坐标相应为a₂，a₃，a₄，…，a₂₀₁₀，则$\frac{1}{a_2}$+$\frac{1}{a_3}$+$\frac{1}{a_4}$+…+$\frac{1}{a_{2010}}$=（　)

   Let me tell you my pen friend Ivan. He is 12 years old. He likes playing football. He usually play football with his friends at weekends.
Ivan lives with his father and mother in a city in France. They have a dream home with five rooms, a swimming pool and a garden. They often have a party in the garden at weekends. They like to help their neighbours. His home is not near his school, so Ivan takes a bus for an hour and then walks for 10 minutes to school. There is a Basketball Club near his school. He likes play basketball in the club.
   Ivan's father is a worker. He is busy. Ivan's mother is a doctor. She is nice to the patients. Ivan wants to be a teacher when he grows up. I want to be a teacher, too. Every month Ivan writes two letters to me. He'll come to Suqian next year. We'll meet then.