—Did you have a good time at the party.

—Yes, we enjoyed _______ very much [ ]

A. ourselves

B. myself

C. yourself

D. yourselves

好氧生物稳定塘的池深一般仅为0.5m左右，这主要是因为

A．因好氧塘出水要求较高，便于观察处理效果

B．防止兼性菌和厌氧菌生长

C．便于阳光穿透塘体利于藻类生长和大气复氧，以便全部塘体均处于有溶解氧状态

D．根据浅池理论，便于污水中固体颗粒沉淀