股肿多发生于（）

[单选题]急惊风湿热疫毒证的主症是（）

[单选题]Questions 21 to 25 are based on the following passage. Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly. A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic (北极的) snow were declining. In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States. In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline. Many scientists had believed that the lead would stay in soil and snow for a longer period. The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected. Scientists say both studies demonstrate that certain parts of the ecosystem (生态系统) respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute. The study published in the journal Nature indicates that （）

[单选题]反映一个国家的保险在社会生活中的普及程度的一个重要指标是（）。

[单选题]儿童知道手脚是自己身体的一部分，说明其处于(  )

[单选题]诊断直立性低血压是根据（）

[单选题]踱烧伤局部水疱形成的主要病理基础是（）

[单选题]预防心脑血管疾病的关键在于从小注意减少可能引起该病的（）

[名词解释题]无功

[单选题]清除内存命令，可以清除（）窗口

[多选题]“逻辑性”在提问中的重要性体现在（）。