— _______ do you go to school?
— I go by bus.
A:What
B:Why
C:When
D:How
某农技站货架上待售的化肥有NH4NO3、KNO3、CO(NH2)2,其中缺少的肥料品种是( )
如图甲是小名同学安装好的直流电动机模型: