例句與造句

1. Its fundamental is that the ray emitted from a focus ( front ) of elliptical will flock together on the other focus ( back ) by the reflection on the elliptical surface . we set a scatter aperture on the back focus
   橢圓柱面的前焦線上是射線源，晶體固定在一個橢圓基底上，其表面構(gòu)成一橢圓柱面， x射線經(jīng)晶體衍射后會聚于后焦線上。
2. It's difficult to find elliptical surface in a sentence. 用elliptical surface造句挺難的