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英语听力文摘 English Digest 535、蚕丝生产的秘密你知多少？

Secrets Of Silk Production Fifteen hundred years ago in China, silk production was a state secret. The silk trade was so valuable that anyone who tried to take silkworm eggs or mulberry seeds out of China was put to death. Then in 552 AD, two monks s

发表于:2018-12-31 / 阅读(48) / 评论(0) 分类 英语听力文摘 English Digest
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