【正确答案】The Annual Spending of USA Universities The bar chart provides an overview of the changes in annual spending of USA universities during the years 2010 to 2012. The proportions of insurance and teachers' salaries have a small upward trend while the percentage of temporary workers' salaries shows a continuous downward trend. Furthermore, the proportions of furniture and equipment as well as resources are fluctuating. These changes may be caused by the following reasons. To begin with, the rise in insurance and teachers' salaries is due to the increase in the employers' awareness of improving employees' welfare. What's more, the economic depression and low employment rate lead to the decline in the temporary workers' salaries. In addition, as time goes by, the fixed assets will be worn out gradually, so that the expenses of furniture and equipment as well as resources are not stable. In my view, these changes are quite normal. However, some measures should be taken to improve the welfare of temporary workers.