单词:gradient-index rod lens
梯度指数杆透镜
单词:gradient-index rod lens 相关文章
Our story is called The Diamond Lens. It was written by Fitz-James O'Brien. Today we will hear the second and final part of the story. Here is Maurice Joyce with part two of The Diamond Lens. When I was a child, someone gave me a microscope. I spent
发表于:2019-01-03 / 阅读(295) / 评论(0)
2018年VOA慢速英语(三)月