题目

阅读理解Long ago, writing was done on parchments一thin, dried animal skins specially prepared for writing. But the parchment wasn't easy to make and it wasn't cheap. Then, ancient people removed the original writing from a parchment and then used it again for another piece of writing. That's what creates a palimpsest. Thewriting removed from the parchment can't be seen directly. Generally, findinghidden writing on very old documents is so unusual, but for scientists, it isjust the opposite because they have learned ways to use special lighting todiscover it. For young college students, do看图写汉字。