人防工程中，火灾疏散照明和火灾备用照明可采用蓄电池作备用电源，其连续供电时间不应少于( )。

A．20min

B．30min

C．60min

D．10min

— Hi, I ____ Tony. _____ you Helen?       

— Yes, I am.

A．am, Am

B．am, Is

C．am, Are

D．is, Are