题目

阅读下面材料，在空白处填入1个适当的单词或括号内单词的正确形式。 The way we cook is important. In many countries, the two choices are (nature) gas or electric ­powered stoves. The World Health Organization warns that millions of people (suffer) from indoor air pollution at present time, which results from the use of (danger) fuels and cook­ stoves in the home. WHO officials say nearly three billion people are (able) to use clean fuels and technologies for cooking, heating and lighting. As a result, more than seven million people die from exposure to indoor or ou一组数据如下：3，6，7，2，3，4，3，6，那么这组数据的中位数是（　　） A、3B、3.5C、3或4D、2