许多成语典故源于历史，如退避三舍、卧薪尝胆、围魏救赵、纸上谈兵等。这些成语反映出春秋战国时期的哪一特点（    ）

. She asked me ________ the film the day before.

       Shenzhou X and three astronauts(宇航员) were sent up from Jiuquan Satellite Launch Center, Gansu province, into a clear blue sky on Tuesday, bringing the nation one step closer to building its own space(太空) station in 2020.
　　Two men, mission commander(指挥官) Nie Haisheng and Zhang Xiaoguang, and China’s second female astronaut, Wang Yaping, are expected to stay in space for 15 days.
　　They will teach young people about science and do two space dockings, between Shenzhou X and the unmanned Tiangong-1 space module, a technically difficult procedure that brings two spaceship together in high-speed orbit(轨道).
　　The trip is our country's fifth manned space mission, 10 years after the country’s first astronaut, Yang Liwei, went into space in 2003.

如图示，摆球带负电，在一匀强磁场中摆动，匀强磁场的方向垂直纸面向里，摆球在AB间摆动过程中，由A摆到最低点C时，摆线拉力为F₁，摆球加速度大小为a₁；由B摆到最低点C时，摆线拉力的大小为F₂，摆球加速度大小为a₂，则（      ）

以下各项最能说明新航路开辟对世界历史发展起到积极作用的是（    ）