题目

The problem of global warming has caused a lot of people to get started on increasing their campaigns to save the Earth’s ecological system.The trouble is that nearly all people think it even expensive to begin living green.Continue reading to see several immediate things you can do to get on the road to living green. You can get on a great start by learning to recycle.While this appears really simple，there are many people who still toss glass bottles and aluminum cans into their common garbage.In the US，it’s easy to locate a trash service that has glass and aluminum recycling a声音在不同介质中传播的速度大小不同。根据以下小资料可知：多数情况下，声音在气体中的速度比液体中的___〔选填“大”或“小”〕，声音在空气中传播的速度受___的影响。小资料：一些介质中的声速v/(m/s)