—Did you call on any of your old friends when you returned to your hometown?

—_______ of them. They were all very busy.

A．Nobody

B．None

C．Both

D．Neither

零时到八九点钟，有许多称谓，如：凌晨、黎明、清晨、早晨等，你知道凌晨是哪一段时间？（）

A、零时至六时 

B、申时到六时 

C、天快亮时 

D、天刚亮时