题干
One of the important lessons children learn from their parents is ________
A：how speaking politely to others
B：how to speak politely to others
C：what time speaking politely to others
D：what time to speak politely to others
答案(点此获取答案解析）
B
m，利用地球同步卫星与地球表面的距离为3.6×
m这一事实可得到哈勃天文望远镜绕地球运行的周期．以下数据中最接近其运行周期的是 ( )