A:c(NH4+) = c(SO42-)
B:c(NH4+)=2c(SO42-)
C:2c(NH4+)=c(SO42-)
D:c(OH-)+c(SO42-) = c(H+)+c(NH4+)
选出下列句子中没有语病的一组( )。
概念图的分析,正确的是( )
—I have trouble learning math this term.
—You should pay more _______ to your teacher's advice.