题目

  Using too much water or throwing rubbish into our rivers are clear ways that humans can put our water supply in danger ,but we also affect our water supply in less obvious ways .You may wonder how paving(铺砌) a road can lead to less usable fresh water. A major part of the water we use every day is groundwater. Groundwater does not come from lakes or rivers .It come from underground. The more roads and parking lots we pave, the less water can flow into the ground to become groundwater.      Human activity is not responsible for all water shortages. Dry climates are of course m在生物圈中，动物之间的信息交流是普遍存在的。