The flight was put off due to the typhoon. Otherwise, we______ the beautiful scenery in Greece now.

A．would be enjoying

B．would have enjoyed

C．will enjoy

D．must have enjoyed

某河流被大量有机物和粪便污染后，使厌氧细菌迅速生长繁殖，在这些微生物的作用下，有机污染物分解，其最终产物是（）。

A.氮气

B.有机氮

C.氨氮

D.亚硝酸盐氮

E.硝酸盐氮