题目内容：

At the beginning of the twentieth century, many people thought that the Americanfamily was falling apart.A century later, we know that this was not the case. However,although the family is still alive in the United States, its size and shape were very different100 years ago.

In the late 1800s and early 1900s, there were mainly two types of families in theUnited States: the extended and the nuclear. The extended family usually includesgrandparents, parents, and children living under the same roof. The nuclear familyconsists of only parents and children.

Today there are many different kinds of families. Some people live in “traditional” families, that is, a stay-home mother, a working father, and their own biologicalchildren. Others live in two-paycheck families, single-parent families, adoptive or foster,families, blended families (where men and women who were married before marry againand combine the children from previous marriages into the new families），childlessfamilies, and so on.

What caused the structure of the family to change? In the early 1900s the birthratebegan to fall and the divorce rate began to rise. Women were suddenly choosing to go tocollege and take jobs outside the home. In the 1930s and 1940s, many families faced seriousfinancial, or money problems during the Great Depression, when many people lost theirjobs. During World War II（1939-1945)，5 million women were left alone to take care oftheir homes and their children. Because many men were at war, thousands of these "war widows" had to go to work outside their home.

During the next ten years, the situation changed. There were fewer divorces, andpeople married at a younger age and had more children than the previous generation. It wasunusual for a mother to work outside the home during the years when her children weregrowing tip. Families began leaving cities and moving into single-family homes in thesuburbs. The traditional family seemed to be returning.

In the years between 1960s and 1990s, there were many important changes in thestructure of the family. From the 1960s to the early 1970s, the divorce rate doubled andthe birthrate fell by half. The number of single-parent families tripled, and the number ofcouples living together without being married doubled again. In fact, the single-parenthousehold, once unusual, has replaced the "traditional" family as the typical family in theStates. If we can judge from history, however, this will probably change again in thetwenty-first century.

The Changes of the American Family

Main comparisons	Contexts
Different___1____	There were two __2___ types of families in the past, ___3____, the extended and the nuclear.
Nowadays __4___types of families can be seen than before.
Changes in different ___5_____.	In the 1900s and 1940s	Many of the women had to work outside due to the __6___of money., thus causing the fall of __7__and the rise of divorce rate.
In the 1950s	Divorce rate slided and there were more children . The families tended to be ___8___ again.
In the years between 1960s and 1990s	Different types of familes__9____. Traditional families are no longer the typical ones in America.
A trend worth noting
Author’s opinion on changes	The present structure is ___10____; it will experience changes again in the near future.