—What's Meimei doing?
—She _ _the piano. [ ]
A. plays
B. playing
C. play
D. is playing
答案:D
1mol CO和1mol CO2具有相同的:①分子数 ②原子总数 ③碳原子数 ④氧原子数( )
A.①③
B.②④
C.①④
D.①②③
下列选项中,不属于SQL数据定义功能的是( )。
A.0.123
B.123000
C. 2.1e3.5
D.123