层状云是由于大气中系统上升运动使空气()生成的。
参考答案:绝热冷却
Unscramble the sentences and questions.
A: see the let's elephants. Let's see the elephants. B: like do you why elephants? (1) A: friendly very because are they. (2) B: they from are where? (3) A: from Africa are they. (4)
西周婚姻成立的条件有()
A.一夫一妻
B.同姓不婚
C.父母之命
D.六礼