--- What should we do on No-smoking Day?

--- People aren’t _________ on that day.

A．allowed smoking

B．allowed to smoke

C．allowing to smoke

D．allow smoking

19世纪末和20世纪初，随着物理学研究内容的拓展和深入，经典力学显现出了其局限性，经典力学只适用于____运动（填“低速”或“高速”）和___世界（填“微观”或“宏观”）。