[单项选择]符合高血钾心电图表现的是（）
A. T波高耸，基底部狭窄，呈帐篷型T波
B. u波倒置
C. 冠状T波
D. ST段水平型下移
E. QT间期缩短

{{B}}America’s Top 5 Cleanest Cities{{/B}}
{{B}}What Is a Clean City {{/B}}
Ideally, it’s a place where the air quality is good, the water is safe to drink, and factories aren’t dumping harmful chemical waste into the environment. It’s also a place where you look up and down streets that are free of garbage, and stroll through parks without wading through litter.
{{B}}San Francisco{{/B}}
{{B}}Background:{{/B}} Once a prominent shipping and manufacturing center, San Francisco now has booming financial and business sectors. Since 1980, the city’s population has increased by more than a third and its per capita income ranks among the nation’s highest. Few places have a citizenry that is more environmentally conscious.
{{B}}Problems:{{/B}} Like nearly every traffic-clogged urban California area, San Francisco has struggled with high emissions of greenhouse gases. Its Hunter’s Point are