题目

If you are planning to study in the United States, you need to consider several factors. Everyone has different opinions about where is the best place to live in. Also, the best places to live in are not always home to the best schools. Finally, many schools specialize in different areas of study. The Massachusetts Institute of Technology, for example, is a great school for computer science and technology-related fields of study. However, if you want to study oceanography（海洋学）, your interests may be better served by attending school in a place that is on a coastline or near t为了减轻大气污染，在汽车尾气排放处加装“催化净化器”装置，可将尾气中的 NO、CO转化为参与大气循环的无毒的混合气体，该混合气体是A.CO2、NH3B.N2、CO2C.O2、CO2D.NO2、CO2