Choose the suitable word to fill in each plank.

The American family has changed greatly in the last 20 or 30 years. Many of these changes are (26) __________ to changes taking place in other countries. Young people do not want to get married or get married early. Women are also waiting longer to have children or even (27) __________ having children.

Families have fewer children. Today most families have one or two children. In a traditional family, the wife stayed at home to take care of her children and to do household (28) __________ while the husband was responsible for earning money. Now, 60 percent married women work outside the home. One reasonfor this change is that women want and expect to have their own jobs. Another reason is economic. With rising prices, many families cannot (29) __________ on one person's salary.

The United States has a high divorce rate. It is estimated that one in every three marriages (30) ____________ in divorce. One result of this high divorce rate is that many American children live in single-parent families. Poverty among children in homes headed by single mothers has become a serious problem in the United States.

He had so a difficult exercise that he couldn't do it.