单项选择题
A．the environmental balance B．our daily life C．the consumption of goods by man D．the whole process of industrial production and consumption of goods
A．The box fell down and hit the man on the head. B．The box continued to go up. C．The man went up to the top of the building. D．The man fell down and broke his legs.
A．He was afraid that someone would steal his box. B．Because he wanted to climb up along the rope. C．He fastened the end of the rope in order to keep the box unmoved. D．Because he wanted to prevent the box from coming down.