A．回顾往事；事后看来
B．符合；与……一致 C．响应 D．数量级
E．就……而言 F．为……铺平了道路；为……奠定基础 G．有一点；有一丝
H．提出；解释 I．提出假设；猜想 J．更不必说 Although the military constantly tracks tens of thousands of objects in
orbit around the earth, the true amount of debris may be an order of
magnitude higher.