A．Because the police could not see them in the dark. B．Because many of them were armed with guns. C．Because there were not enough policemen to catch them all. D．Because they were hidden inside big buildings.

单项选择题

A．Because the police could not see them in the dark.
B．Because many of them were armed with guns.
C．Because there were not enough policemen to catch them all.
D．Because they were hidden inside big buildings.