单项选择题A．It’s cheaper to go to Chicago by car.B．She likes to travel by car.C．She doesn’t know how much it costs to go by train.D．They should guard their money when taking the train.

单项选择题A．Because it was difficult to collect.B．Because it was difficult to get rid of.C．Because it came in a variety of forms.D．Because it tended to be absorbed by physical objects.