Andy has _______ for five years. Five years _________ a long time.

A．come back home, is

B．come back home, are

C．been at home, is

D．been at home, are

舒适性空气调节，空气调节区与室外的压力差或空气调节区相互之间有压差要求时，其压差值不宜取（）Pa.

A、5~10

B、5~15

C、10~20

D、10~15