《2025年高中同步单元滚动强化卷高中英语选择性必修第三册北师大版》

B
The first zoo 1. was established (establish) around 3,500 years ago by an Egyptian queen for her personal enjoyment. Five hundred years later, a Chinese emperor 2. built (build) a huge zoo to show his power and wealth. Later zoos were set up for the purpose of studying animals.
Some of the early European zoos 3. consisted (consist) of dark holes or dirty cages, the bad conditions of which made people disgusted. Later the zoos 4. were replaced (replace) by research centers and animals there were studied and 5. (were) kept (keep) in good condition. These places became the first modern zoos. As early as the 1940s, scientists 6. understood (understand) that many kinds of wild animals faced extinction. Since then, zoos 7. have tried/have been trying (try) to save many endangered species, but relying on zoos 8. to save (save) species is not enough. The best method of protection is to leave them in their natural habitat.
Today, animals in large and natural reserves are fed a balanced diet and 9. (are) watched (watch) carefully for any signs of disease with specially trained keepers looking after them and some hospitals where they can be treated when ill, and all the animals there live a comfortable life. Anyway, it is true that zoo breeding programs 10. are playing (play) an important role in protecting many species of wildlife now.

答案： 1.was established 2.built 3.consisted 4.were replaced 5.(were) kept 6.understood 7.have tried/have been trying 8.to save 9.(are) watched 10.are playing

Cloning is the process of making an exact copy of a plant or animal and developing it either naturally or artificially. Natural cloning 1. has been going (go) on for generations. For example, gardeners take a cutting from a plant and place it in a suitable medium. For years, there had been attempts 2. to clone (clone) animals artificially. The first successfully cloned animal was a sheep 3. named (name) Dolly in 1996. Dolly grew 4. normally (normal) at first, but later she developed an illness. She lived only half the life of the sheep from which she was cloned. Scientists have also found the similar pattern of health problems in other cloned 5. animals (animal). In January 2018, the two cloned long-tailed monkeys 6. were announced (announce) by Chinese scientists. They were the first-ever primates, 7. which proved to be “much harder”. The success has led to worldwide praise as a huge breakthrough. This might lead to cures 8. for various diseases and offer clues on how to prevent the aging process. However, cloning continues to be an issue that causes a great deal of 9. disagreement (disagree) and provokes strong emotions. 10. While some people believe it is crucial for scientific advancement, others raise moral concerns. They believe it is bound to lead to cloning of other species, and they worry about the ethical questions this raises. Researchers insist that the science of cloning should be further explored and advanced.

答案： 1.has been going 2.to clone 3.named 4.normally 5.animals 6.were announced 7.which 8.for 9.disagreement 10.While