为达到理想的视觉效果有时还会加入颜料和染色剂.Pigments and tints are sometimes added to achieve the desired visual effect.用对比染色剂染 ( 显微术样本 )To color ( a microscopic specimen ) with such a stain.汽水中使用的染色剂也是一种致癌物质.Colorings used in sodas are canc...
他们把望远镜转向附近其他星系。They turned their telescopes towards other nearby galaxies.类星体是遥远星系的极为活跃的核心体.Quasars are the highly energetic cores of distant galaxies.我们还不知道宇宙中有多少个星系.We still don't know how many galaxies there are ...