题型：阅读理解 题类：常考题 难易度：普通
江西省南昌市八一中学2020-2021学年高二下学期5月份英语考试卷
Iman, the last Sumatran rhino(犀牛) in Malaysia, died in 2019 — bringing the endangered species one step closer to extinction. Now, Malaysian scientists are hoping to use tissues and cells from Iman and other dead rhinos to bring the population back.
"Before the three rhinos (the last survivors in Malaysia) died, we got their cells, and the cells are still alive — which is why I'm quite confident," Dr. Lokman said. "If we don't have any cells, or have just tissue that isn't living anymore, we wouldn't be able to do anything. But now we have a living thing that we can use. "
The cells came from the rhinos'hearts, lungs and brains. What is the most important is that the team collected stem cells (干细胞). One possible approach is to develop these stem cells into an egg (卵子) and sperm (精子), to create an embryo (胚胎) that will be placed into a surrogate mother (代孕母亲). She will likely be another rhino, either a Sumatran rhino from another country or another species. The other method is to take the egg of a surrogate animal, remove the nucleus (细胞核), and join it with a Sumatran rhino's body cell. This technique was famously used to clone Dolly the sheep in 1996. Dr. Lokman and his colleagues are trying both ways. The team is still in the early stages; next, they need to find a suitable surrogate female.
Sumatran rhinos are listed as critically endangered by the World Wildlife Fund. There are less than 80 alive in Indonesia and Thailand. The fall in the population was first caused by hunting. Later, the situation was worsened by the loss of habitats and human activity. Unfortunately, there are now only five remaining rhino species worldwide, and all are threatened. Some sub-species have already died out; the western black rhino was declared extinct in 2013. And it is a pity that the last male northern white rhino died in 2019.
Reducing the amount of sleep affects students' performance at school. An American study asked schoolteachers to look at the effects of sleep restriction（限制） on children between six and twelve years of age. The teachers found that children who stayed up late had trouble thinking clearly and had more learning problems.
{#blank#}1{#/blank#} Doctor Fallone now works at the Forest Institute of Professional Psychology in Springfield, Missouri. He presented the results last month at a science reporter conference in Washington, D. C. The Publication Sleep also reported the findings.
The teachers were asked to complete weekly performance reports on seventy-four schoolchildren. The study lasted three weeks. During that period, Doctor Fallone and his team controlled the amount of sleep the children received.
{#blank#}2{#/blank#} During another week, every child was kept awake later than normal. Each night, the youngest boys and girls had less than eight hours of sleep. The older ones were limited to six and a half hours. During the final week of the study, each child received no less than ten hours of sleep a night.
The teachers were not told about how much sleep the students received. The study found that students who received eight hours or less had the most difficulty remembering old information. {#blank#}3{#/blank#}
The study did not find that sleep restriction caused hyperactivity(极度活跃) in the children. {#blank#}4{#/blank#}
Doctor Fall one said that the results provided experts and parents with a clear message: {#blank#}5{#/blank#}
A. The sleeping time that the students have can be changed easily. B. They also had trouble learning new information, completing difficult work and following directions. C. During one week, the children went to bed and awoke at their usual time. D. The teacher should restrict the amount of sleep of the students. E. Gahan Fallone did the study at the Brown Medical School and Bradley Hospital in the state of Rhode Island. F. The teachers reported that students were, in fact, a little less active at school when they got less sleep. G. When a child has learning problems, the issue of sleep must be considered among the possible causes. |
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