题目

According to a U.S. survey, one third of all school aged children in the United States are, for some part of the week, latch key kids; that is, they go home to an empty house. The total number may be between five and seven million children between 5 and 13 years old. The survey found that 15% were home alone before school, 76% after school and 9% at night. Perhaps, the 9% have parents who work at night. One-half of all children in the country aged 12 to 14 are home alone an average of seven hours a week. The very poor in America are less likely(可能) to leave their children alone at home, o世界年平均气温分布图上，南半球等温线比较平直，原因是南半球A．地势低平B．平原面积广阔C．海洋广阔D．山地面积广阔