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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 smuggled silkworm eggs to Co

发表于:2018-12-28 / 阅读(63) / 评论(0) 分类 初学者听力文摘精选

Survival Of The Sluggish Silkworms have been bred over thousands of years to behave quite unlike their caterpillar cousins in the wild. Thats because people purposely breed silkworms to fit this job description: WANTEDSuperlative silk producers. Bene

发表于:2018-12-31 / 阅读(30) / 评论(0) 分类 英语听力文摘 English Digest

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(27) / 评论(0) 分类 英语听力文摘 English Digest

Once upon a time there was a princess who was ever so proud: if any man came to woo her she would set him a riddle, and if he couldn't guess it he was laughed to scorn and sent packing. She also had it made known that whoever did guess the answer to

发表于:2019-01-06 / 阅读(93) / 评论(0) 分类 阅读空间

1500年以前,丝绸的生产是中国的国家机密 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

发表于:2019-01-26 / 阅读(55) / 评论(0) 分类 英语听力文摘 English Digest

Silkworm s and Skin Graft s Don: One of the neater things thats going on in biology is the genetic modification of species. By changing the instructions in their genes, we can make certain plants and animals produce things that are useful to humans.

发表于:2019-02-16 / 阅读(35) / 评论(0) 分类 英语听力文摘 English Digest