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Conventional wisdom says that hardship can make us old before our time. In fact, a new study suggests that violence not only leaves long-term scars on children’s bodies, but also changes their DNA, causing changes that are equal to seven to ten years of premature aging (过早老化).
Scientists measured this by studying the ends of children’s chromosomes (染色体), called telomeres, says Idan Shalev, lead author of a study published in Molecular Psychiatry.
Telomeres are special DNA sequences (序列) which prevent the DNA in chromosomes from separating. They get shorter each time a cell divides, until a cell cannot divide any more and dies.
Several factors have been found to shorten telomeres, including smoking, radiation and psychological stresses such as being treated badly when young and taking care of a chronically ill person.
In this study, researchers examined whether exposure to violence could make children’s telomeres shorten faster than normal. They interviewed the mothers of 236 children at ages 5, 7 and 10, asking whether the youngsters had been exposed to domestic violence between the mother and her partner, physical maltreatment by an adult or bullying. Researchers measured the children’s telomeres—in cells obtained from the insides of their cheeks—at ages 5 and 10.
Telomeres shortened faster in kids exposed to two or more types of violence, says Shalev. Unless that pattern changes, the study suggests, these kids could be expected to develop diseases of aging, such as heart attacks or memory loss, seven to 10 years earlier than their peers.
Shalev says there is hope for these kids. His study found that, in rare cases, telomeres can lengthen. Better nutrition, exercise and stress reduction are three things that may be able to lengthen telomeres, he says.
The study confirms a small­but­growing number of studies suggesting that early childhood hardship imprints itself in our chromosomes, says Charles Nelson, a professor of pediatrics and neuroscience at Harvard Medical School.
【小题1】The new study has found that ________.
A．violence leaves scars on a child’s mind
B．violence can speed up a child’s aging
C．hardship can change a child’s aging
D．hardship has a long-term effect on children
【小题2】According to the text, telomeres ________.
A．probably cause a cell to divide quickly
B．can help prevent DNA from separating
C．can make a cell die quickly
D．become shorter before they die
【小题3】All of the following things can shorten telomeres EXCEPT ________.
A．maltreatmentB．radiation
C．smokingD．exercising
【小题4】Which of the following is TRUE, according to the text?
A．Researchers measured the children’s telomeres from their legs in the study.
B．Kids interviewed in the study are exposed to two or more types of violence.
C．Children who have shorter telomeres may suffer from a heart attack earlier.
D．Victims of domestic violence have no hopes of lengthening their telomeres.
【小题5】What is the best title for the text?
A．Violence aging children’s DNA
B．Children’s changing DNA patterns
C．Violence and children
D．The function of telomeres
答案：【小题1】B
【小题2】B
【小题3】D
【小题4】C
【小题5】A
试题分析：本文主要讲述暴力不仅对孩子的身体有长久的影响，还会引起DNA变化，导致过早老化
【小题1】B细节理解题。根据第一段第一句a new study suggests that violence not only leaves long-term scars on children’s bodies, but also changes their DNA, causing changes that are equal to seven to ten years of premature aging (过早老化).这份新的研究指出暴力不仅给孩子身体造成长久伤痕，而且改变其DNA引起过早老化，可知暴力会加速孩子变老，故选B
【小题2】B细节理解题。根据第三段第一句Telomeres are special DNA sequences (序列) which prevent the DNA in chromosomes from separating端粒防止DNA分离，故选B
【小题3】D细节理解题。根据第四段第一句Several factors have been found to shorten telomeres, including smoking, radiation and psychological stresses such as being treated badly可知只有锻炼不能使端粒变短，故选D
【小题4】C细节理解题。根据倒数第三段第一句Telomeres shortened faster in kids exposed to two or more types of violence, says Shalev. Unless that pattern changes, the study suggests, these kids could be expected to develop diseases of aging, such as heart attacks端粒更短的孩子，研究表明，更可能发展出老化疾病如心脏病，故选C
【小题5】A归纳概括题。本文主要讲述暴力不仅对孩子的身体有长久的影响，还会引起DNA变化，导致过早老化，故本文最好标题是暴力老化DNA，故选A
考点：考查科技文阅读
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