教室里贴有大小同样的四幅地图,按比例尺由小到大排列的是( )
①济南地图 ②山东省地图 ③中国地图 ④世界地图.
A:①②③④
B:④③②①
C:①③②④
D:③④②①
— He made few mistakes in his speech, ______________? — ____________, his performance is wonderful.
下列物质中,由阴、阳离子构成的是 ( )