下列比例尺中,最小的是( )
A:1:500
B:1:40000
C:图上1厘米代表2000千米
D:1:3000000
将25g20%氯化钾溶液稀释到50g,稀释后所得溶液中溶质的质量分数是( )
—______ you ______ he goes there. Only one student is needed.