--______ is your house from the factory?  --It’s about twenty minutes’ walk.

A．How long

B．How soon

C．How often

D．How far

隧道内仰拱、底板混凝土应整体浇注，一次成型。仰拱与仰拱填充混凝土（）施工，仰拱底部虚碴、杂物、积水必须清理干净。