_______ in the city for thirty years, the old man moved back to the countryside.

A．Having worked

B．Working

C．To have worked

D．To work

下列属于消火栓箱按箱门型式分类的有（）。

A．左开门式 

B．右开门式 

C．双开门式 

D．前后开门式 

E．卷盘式