【简答题】阅读理解。 In ancient Egypt, the pharaoh (法老) treated the poor message runner like a prince when he arrived at the palace, if he brought good news. However, if the exhausted runner had the misfortune to br...
【单选题】The Huygens-Fresnel principle tells us to pretend that each point of a wavefront in a slit or aperture is a point source of light emitting a spherical wave. Is this true only for points inside the sli...