Traditionally,(状语，修饰全句) all the members of an extended family lived in the same area. However, with the change from an agricultural to an industrial society, many nuclear families moved away from the family home in order to(so as to ) find work. In industrial societies today, the members of most nuclear families live together, but most extended families do not live together. Therefore we can say that the nuclear family becomes more important than the extended family as the society industrializes.       In post-industrial societies like the United States, even the nuclear family is changing. The nuclear family is becoming smaller as(because) parents want fewer children, and the number of childless families is increasing. Traditionally, the father of a nuclear family earned money for the family while the mother cared for the house and the children. Today, more than 50% of the nuclear families in the United States are two-earner families -- both the father and the mother earn money for the family -- and in a few families the mother earns the money while the father takes care of the house and the children. Many nuclear families are also splitting up -- more and more parents are getting divorced.   What will be the result of this splitting of the nuclear family?  Social scientists now talk of two new family forms: the single parent family and the remarried family. Almost 20% of all American families are single parent families, and in 85% of these families the single find it  difficult to take care of a family alone, so they soon marry again and form remarried families. As social scientists study these two new family forms, they will be able to tell us more about the future of the nuclear family in the post-industrial age.       Sibling   DINK= double income and no kids   Who will in charge of your class ?   That is,    or        I will take the umbrella if it rains.   As soon as he comes , he will tell me the truth.   Generate-----generation gap   part   He plays an important role in our class.       physical exercises\examination   Labor--------mental   emotionless   provide sb. With sth.= provide sth. For sb.   Supply --- offer   prepare   Main--- key----essential   predict   prefix   depend on\upon------dependence   independent from------independence   give up smoking-----give it up   we went to the Summer palace instead of going to the zoo.   He is busy preparing for his exam.   Be busy with doing   Can’t help(from) doing   I couldn’t help crying when I read the story.