题目

Traffic restrictions have come into effect in Beijing      to improve the  capital’s air quality and traffic situation for the 2008 Olympics．      A．in order that    B．in an attempt     C．at an attempt    D．in a try 答案：B 解析: in an attempt to do sth努力尝试做某事。下列对实验现象的描述正确的是（　　）A. 打开浓盐酸瓶塞，产生大量的白烟B. 光亮的铁丝浸入稀盐酸，形成黄色溶液C. 镁条在空气中燃烧，发出耀眼白光D. 浓硝酸滴入鸡蛋清，蛋清凝固变白