Questions 18-21 are based on a conversation you are going to hear.

What does the woman think the man should do

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

A．buy
B．sell
C．race
D．see