A:丙烷的比例模型是
B:C2H4与C3H6一定互为同系物
C: 属于芳香烃
D:羟基的电子式为 ,1mol﹣OH含有7mol电子
在空中水平匀速飞行的救灾飞机不停地往灾区丢救灾物资,在此过程中,飞机的机械能 ____(选填“变大”“变小”“不变”)
George is going to talk about the geography of his country,but I’d rather he________more on its culture.
张华上午骑车行了84千米,下午骑车行3小时,求张华每小时行多少千米.列式是:84÷3