A supernova sprays space with many different elements.超新星会向宇宙放射不同种类的元素。At least one supernova occurs per decade in our galaxy.在我们的星系中每 10 年至少有一颗超新星出现。The ejected mass then probably becomes the observed material of a supe...
她把包装盒子的玻璃纸撕了下来。She tore the cellophane wrapping off the box.玻璃纸系由长形纤维分子组成.Cellophane is made of long, fibrous molecules.插入红色或蓝色的玻璃纸,观察条纹宽度的变化.Interpose red or blue cellophane and observe the change in the width of the fr...