Unit 9 Unit 1 课文练习-2022-2023学年高中英语北师大版（2019）选择性必修第三册

北师大版高中英语新教材(选择性必修第三册)课文（Unit 9| LESSON 1) Lesson 1 To Clone or not to Clone?  第一课 克隆还是不克隆 1. ________ (克隆) is the process of making an exact 2. ________ (复制) of a plant or animal and developing it either naturally or 3. ___________ (人工的). Natural cloning has been going on for generations. For example, gardeners have been using a form of cloning when they take a cutting from a plant and place it in a suitable medium, such as soil. Another example of natural cloning is 4. ________ (完全相同的) 5. ________ (双胞胎), who are produced from the same egg. For years, there had been attempts to clone animals artificially. The first successfully cloned animal was a sheep named Dolly in 1996. At first, Dolly grew normally, but later she developed an illness that is more normally found in much older animals. She lived for six and a half years, only half the life of the sheep from which she was cloned. After Dolly, scientists have cloned more than 20 6. _________ (哺乳动物) species, including 7. ________ (骆驼),