All of them are astonished, because such a thing has never（）(hear) of before.

A．very old people enjoy living with their relatives
B．social services have nothing to do with the very old people
C．some old people like to live alone to have more personal freedom
D．no one is willing to take care of very old people

A．planes and motorcars have taken the place of trains
B．oil is expensive today
C．trains are super fast
D．railways earn a large amount of money