题目

阅读理解TheEarth is losing some of its major freshwater supplies. But the water is not inlakes or rivers. They are called aquifers (含水层). They formed deep underground as the Earth developed. Someaquifers are so deep that water from very heavy rains cannot reach them throughall the rock and dirt.Manyaquifers provide irrigation (灌溉)water forcrops. These freshwater are helping farmers in many countries. A new reportsays some aquifers are being emptied.Irrigatedagriculture is responsible for about 80 percent or more of freshwater useworldwide. A growing part of that comes from underg一束平行光照到平面镜上，那么，它们的反射光线应是A. 会聚的B. 发散的C. 平行的D. 无法判断