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为何单重态氧在苯和丙酮中的寿命不I司?

【参考答案】

与单重态氧在丙酮中的寿命(50μs)相比，在苯中的寿命(30μs)短，反映了苯中由于碳是sp2杂化......

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Preventing Child Maltreatment(虐待）Child maltreatment is aglobal problem with serious life-long consequences. There are no reliable global estimates for the prevalence (流行） of child maltreatment. Data for many countries, especiallylow-and middle-income countries, are lacking.Child maltreatment iscomplex and difficult to study. Current estimates vary widely depending on the country and the method of research useD.Nonetheless,international studies reveal that approxi-mately 20% of women and 5～10% of men reportbeing sexually abused as children,while 25～50% of all children report being physically abuseD.Additionally, many children are subject to emotional abuse(sometimesreferred to as psychological abuse and neglect).Every year,there are about31,000 homicide(杀人)deaths in children under 15. This number un-derestimates the trueextent of the problem,as a significant proportion of deaths due to childmaltreat-ment are incorrectly attributed to falls, burns and drowning.Child maltreatment causessuffering to children and families and can have long-term conse-quences.Maltreatment causes stress that is associated with disruption in early braindevelopment. Ex-treme stress can impair(伤害)the development ofthe nervous and immune(免疫)systems. Consequent-ly,as adults,maltreated children are at increasedrisk for behavioural, physical and mental health prob-lems. Via(通过)the behavioural andmental health consequences, maltreatment can contribute to heart disease,cancer, suicide and sexually transmitted infections.Beyond the health consequencesof child maltreatment, there is an economic impact, including costs ofhospitalization,mental health treatment, ch ild welfare, and longer-term healthcosts.A number of risk factors forchild maltreatment have been identifieD.These risk factors are not present inall social and cultural contexts, but provide an overview when one attempts tounderstand the causes of child maltreatment.It is important to emphasizethat children are the victims and are never to blame for maltreatment.A numberof characteristics of an individual child may increase the likelihood of beingmaltreated, such as being either under four years old or an adolescent, beingunwanted,or failing to fulfill the expecta-tions of parents and having specialneeds crying persistently or having abnormal physical features.International studies reveal thatA.many children have been neglectedB.child maltreatment is most serious in developed countriesC.20% of children have been sexually abusedD.25~50% of girls have been physically abused
A.B.Nonetheless,international
C.Additionally,
D.
E.
F.Maltreatment
G.
H.
I.
J.A
K.
International
L.many
M.child
N.20%
O.25~50%
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