A．To explain why we feel discontented during holidays and immediately after holidays.
B．To show that holidays do harm to people' s health because we feel tired and uncomfortable.
C．To ask people to keep on working during holidays so that the body clock will not be disrupted.
D．To show the fact that people actually don' t enjoy their holidays.

A．he wanted to keep the old green velvet on the top of the chair
B．he found the author amusing
C．he thought he could sell the chair for a profit
D．The author begged him to do so