Mary _____________ ping-pong on weekends. [ ]
A. plays
B. am play
C. playing
D. is plays
答案:A
儿童皮肤和肺蒸发的水分为"不显性失水",是调节人体体温的一项重要措施,此年龄的失水量为每小时多少毫升/每千克体重()
A.2.0~2.5
B.1.0~1.6
C.0.8~1.0
D.0.6~0.7
E.0.5~0.6
足球是圆。[ ]