裂解气碱洗不合格，会造成分子筛中毒，干燥器出口水分会提前不合格，正确的处理方法是（）。

A．立即关闭裂解气干燥器的进出口阀

B．尽快调整碱洗，碱洗合格后投用备用台

C．立即切换至备用台

D．分离系统紧急停车

— Let's go to the zoo by taxi, _____?

— Maybe we can go there ______. It's not far. [ ]

A. won't you, on foot

B. won't you, by foot

C. shall we, by foot

D. shall we, on foot