Removing snowin severe winterisa hard taskin northern citiesof ourcountry. Havingnotbeen cleaned outof the snowon time, the snow will bring about many problems to traffic and so in cities. In winter 2002, a melting snow reagent was used for removing snow instead of traditional brine. In spring of 2003, a great numberof treesdied on some streetsin Beijing. According to a preliminary statistic, the direct lose was millions of china yuan. This paper introduces the main chemical components of the melting snow reagent and discusses the principles of improving the effect of melting snow. It also analyzes why those trees died and offer some advices for use of melting snow reagent.

This paper reviews the discovery of kojic acid,the principle of preparation,and its applications in fresh keeping、anti -enzymatic browning、meat food preservation cosmetology.

Constructionism is reflected to some extent in the national curriculum standards of chemistry, with the emphasis on scientific inquiry, learning environment and cooperative learning. But constructionism itself, it also has some defects, the curriculum implementer should know this clearly.