四级作文题目： Changes in the Ownership of Houses in China
　　It can be seen from the chart that there have been dramatic changes in the ownership of houses in China in the past 50 years. While the percentage of state-owned houses has dropped from 70% in 1950's to 20% in 1990's, that of private houses has soared from 30% to 80% during the same period of time.
　　A number of factors could account for the change in the chart, but the following are the most critical ones. First, thanks to the policy of reform and opening-up, the nation's economy has been developing at a considerably high speed in the past decades. Therefore, people have more extra money to improve their housing. Secondly, other relevant state policies and the boom of real estate industry provide citizens with more opportunities to choose their own dwelling places. Last but not least, people have attached greater importance to their quality of life. Thus more of them have purchased houses in their own favor.
　　In a word, this chart is a perfect index of China's fast expanding economy and people's rising standard of living. Although a series of problems have arisen in the process, it is reasonable for us to believe that they can be solved in the near future with effective measures taken by both the government and the public.