My father returned at 10 o'clock ______ of June 15.
A:in the night
B:by the night
C:on the night
D:at night
表面积____ dm3 ,体积____ dm3
一定条件下的可逆反应2NO2⇌2NO+O2,在密闭容器中达到化学平衡状态的标志是( )