题目

Cities with high levels of homeownership—in the range of 75%, like Detroit and St. Louis—had on average considerably lower levels of economic activity and much lower wages and incomes. Far too many people in financial problems are trapped in homes they can’t sell, unable to move on to new centers of opportunity.     The cities and regions with the lowest levels of homeownership—in the range of 55% to 60% like Los Angeles and New York—had healthier economies and higher incomes. They also had higher levels of happiness and well-being. I was shocked to read these interesting在25℃时，向饱和的澄清的石灰水中加入少量氧化钙，恢复到25℃时，关于该溶液的下列说法中正确的是 （　　）A．溶质质量不变B．溶质质量减少C．溶质质量分数减小D．溶质质量分数变大