当m-n=-2时,原式=m2-2mn+n22=(m-n)22=(-2)22=2
2008年北京奥运会火炬传递的境外路线以古丝绸之路为主线设计。在历史上,古丝绸之路是
①东西方贸易往来的重要通道 ②沟通中西交通的陆上要道
③东西方文化交流的桥梁 ④横跨亚欧的洲际铁路 [ ]
A.①②③
B.①②④
C.①③④
D.②③④
Yesterday I was walking downstairs when I missed my foot and had a bad fall, nothing serious _______.
A even B either C then D though