A:单位时间内消耗n mol X同时生成2n mol Z
B:单位时间生成a molX同时生成3a molY
C:X、Y、Z的浓度不再变化
D:X、Y、Z的分子数之比为1∶3∶2
— What class are you in?
— I'm in , .
计算:(﹣1)2+| 2 ﹣1|+2sin45°.
—Father's Day is coming. Could you tell me ________? —What about a watch? He'll like it.