三个人坐在一排八个座位上,若每人的两边都要有空位,则不同的坐法种数为____
A.水的沸腾
B.水的电解
C.水的净化
— I visited the Purple Mountain Observatory last Sunday.
一 _______ Why didn't you tell me earlier?
猜谜语:
(1)对症下药(打一数学名词)____ ;
(2)0 1 2 5 6 7 8 9 (打一成语)____ ;
(3)你等着我,我等着你(打一数学名词)____ .