| 1. | Just as a double convex lens enlarges , so a double concave lens reduces
正象双凸透镜可以放大那样，双凹透镜也可以缩小。 |
| 2. | This setup , known as a conoscope , is shown in figure 14 . 2 and consists of two stress - free plano - convex lenses a and b
此装置称为锥光镜，如图14 2所示，它由a和b两个无应力平凸透镜组成。 |
| 3. | However , spectacles are made of thick convex lens . skills and precautions are needed to wear contact lens properly . both are not suitable for the elderly
不过，这些眼镜片有相当的厚度，配戴隐形眼镜亦需要一些特别技巧，对于年纪较大的患者未必适合。 |
| 4. | This setup , known as a conoscope , is shown in figure 14 . 2 and consists of two stress - free plane - convex lenses a and b and a diaphragm c having a small aperture
此装置称为锥光镜，如图14 2所示，它由a和b两个无应力平凸透镜和一个带小孔的光阑c组成。 |
| 5. | However , spectacles are made of thick convex lens . skills and precautions are needed to wear contact lens properly . both are not suitable for the elderly
不过，这些眼镜片有相当的厚度，配戴隐形眼镜亦需要一些特别技巧，对于年纪较大的患者未必适合。 |
| 6. | Since lenticular clouds look like one or more convex lens , they could sometimes be misinterpreted as flying saucers or unidentified flying objects , and so they are commonly known as " flying saucer clouds "
由于这类荚状云形状像一块或多块凸透镜，有时候被误会为飞碟或不明飞行物体，所以亦俗称飞碟云。 |
| 7. | Analysis showed this might be due to the fact that a black hole passed in front of the star . the gravitation of a black hole can function as a convex lens and focus starlight , resulting in transience increase of apparent brightness of the star
分析显示，这很可能是因为有一个黑洞在恒星前面经过，黑洞的引力会聚了星光，就像凸透镜把光线聚焦一样，使恒星的视亮度增加。 |
