题目

    America has long been considered the land of opportunity(机遇)by those from other countries. Americans, too, believe that the United States gives almost limitless opportunity for those who want to open business on their own.     Today, Americans are still fond of trying their hand at becoming small business people, even though only one out of two survives in the first two years. Many of these people start their business for the wrong reason: to get away from the paper work of their present jobs or to exchange the responsibility(责任)of their present jobs for free life styles. But生活离不开化学，下列认识错误的是 A．氦气可用于填充安全气球 B．用硬水洗涤衣物，既浪费肥皂，也不易洗干净衣物 C．用洗涤剂除油污是因为洗涤剂能将油污溶解，形成溶液 D．在管道煤气中添加微量难闻的气体是为了及时发现煤气泄漏