雨滴在空中匀速下落的过程中,雨滴的动能_________,重力势能_________,机械能_________.(填“变大”“变小”或“不变”)
不变;变小;变小
The population of many Alaskan cities has ______ doubled in the past three years.
A.as great as
B.as many as
C. more than
D.larger than
患者,女,33岁。既往体健。突然发生多尿2周,明显口渴,多饮,每日约饮水6~7L。初步考虑尿崩症。
下列哪种症状或体征与尿崩症无关()
A.周期性瘫痪
B.头痛
C.可有精神症状
D.高钠血症
E.乏力