题目

阅读理解Each nation has many good people who help to take care of others. Forexample, some high school and college students in the United States often spendmany hours as volunteers in hospitals, orphanages or homes for the aged. They readbooks to the people in these places, or they just visit them or listen to theirproblems. Other young volunteers go and work in the homes of people who are sickor disabled. They paint, clean up, or repair houses, do their shopping and mow theirlawns(修整草坪). For boys who no longer have fathers, there is an organization calledBig Brothers. College stud下列说法中正确的是（　　）A. ﹣a表示负数 B. 近似数8.7万精确到十分位C. 立方根是它本身的数只有0 D. 最大的负整数是﹣1