单项选择题
A．they had big families B．they lived with their children C．the young were kind to the old D．the society didn't change so rapidly
A．often go to clubs with their brothers and sisters B．prefer lonely life to social life C．live more happily than their parents and grandparents D．like to share their feeling and thoughts with other people
A．fewer customers buy them B．more and more of them are produced C．their quality becomes poorer D．more manufacturers produce them.