题目

Taking at least twenty minutes out of your day to walk or sit in a place that makes you feel in contact with nature will significantly lower your stress hormone levels. That's the finding of a study that has established for the first time the most effective amount of an urban nature experience. Healthcare professionals can use this discovery to prescribe (开药) “nature-pills in the knowledge that they have a real measurable effectWe know that spending time in nature reduces stress, but until now it was unclear how much is enough, how often to do it, or even what kind of nature experience w12、美国前国务卿贝克曾说：“苏联的崩溃产生了一个世纪才有一次的机会在全世界推行美国的利益和价值观念。”这反映出（   ） A．苏联的解体使美国成为世界上惟一的超级大国 B．苏联的利益和价值观念曾击溃了美国 C．美国企图规划未来的国际秩序，构筑以自己为主导的单极世界w D．当今世界不得不赞成美国领导下的世界单极格局