This is my family. I  1  a big family. My father is a  2 . He  3 in a hospital. My mother is a nurse.  4 works in the hospital, too. I have 5 uncle. He is my father's  6 . He drives a car. Susan is his wife(妻子). She is 7 aunt. She is a teacher and she works in a  8 . They have  9  kids. Bob is their son, and Amy is their  10 . We all love our family.

如图，C、D是线段AB上两点，若CB＝4cm，DB=7cm，且D是AC的中点，则AC的长等于(    )

2016年6月，“中国好老师腾讯网2016明星教师风采大赛”正式启动。之所以要宣传、展示“中国好老师”，是因为老师（    ）

①是老师，教给我们做人的道理                                               ②是老师，让人产生探求知识的愿望，帮助我们掌握科学文化知识和技能

③给我们做出榜样，教我们思考方法和激发求知的愿望       ④比从事其他职业的人更高贵是老师

顾炎武说：“封建（指分封制）之失，其专在下，郡县之失，其专在上。”对此正确的理解是（  ）