求翻译：过去的20年，人们的生活发生了很大的变化。过去，人们通过寄信与亲戚朋友保持联系，人们从收音机上听新闻或其他信息。孩子们过去常常骑车上学，大的家庭不得不分享一些小房间。是什么意思？

Past 20 years, great changes have taken place in people's lives. The past, people by yourself keep in touch with friends and relatives, people listen to the news on the radio, or other information. Children used to go to school by bike, big families had to share some of the small room.