A～H都是初中化学中的常见物质，它们之间的转化关系如图所示．A是天然气的主要成分，E是一种常见的食品干燥剂．请回答：

俾斯麦曾说:“欧洲存在着不可调和的两个大国,都希望把世界变成自己的属地。”这“两个大国”在第一次世界大战前最有可能是(  )

①拆散了英日同盟               　  ②取得了与英国相等的制海权

③打破了日本独霸中国的局面       　④确立了美国在亚太地区的霸权

阅读下面材料，在空白处填入适当的内容（1个单词）或括号中单词的正确形式。

    Today so many people are talking about AIDS, for which, ____ (fortunate)，there is no cure now. When we talk about its influence on our society, this disease is ____ most severe public health problem of all that we are facing in the 21^st century. It is spreading at a(n) ____ (surprise) speed, especially in Africa.

    The UN AIDS organizations have come to the ____ (conclude) that in the past 20 years, 20 million people have died of AIDS. And this figure will be three times bigger in the next two decades ____ measures are taken in poor countries. Only if people change their basic behavior in time, can AIDS ____ (stop) from spreading. For example, in San Francisco, the rate fell greatly when a serious program was carried out. People were ____ (please) to change their behavior when they realized how serious a risk they were taking.

    Experts think in order to get the message across to those ____ don't realize the seriousness of AIDS, a well ____ (design) educational campaign is the only thing at the moment that can help. It would be criminal not to put it into practice. So everyone has a share of responsibility in the fight ____AIDS.