About two thirds of the population in China ______ in the countryside.

A．Excessive heat probably made people switch on too many electrical appliances.
B．During a storm, lightning damaged supply cables.
C．Because of unemployment, some machines were not in proper working order.
D．The passage does not mention the cause.

A．There were not enough policemen to catch them all.
B．Many of the looters were armed with guns.
C．The police could not see them in the dark.
D．They were hidden inside big buildings.