题目

This seemed like money for nothing. There were millions of frogs in the fields around, and they were no use to the villagers. All they had to do was catch them. Agreement was reached, and the children were sent into the fields to catch frogs. Every week a truck arrived to collect the catch and hand over the money. For the first time, the people were able to dream of a batter future. But the dream didn’t last long.      The change was hardly noticed at first, but it seemed as if the crops were not doing so well. More worrying was that the children fell ill more often, and, there se（题文）亚洲与非洲分界线是______，亚洲很多发源于中部______、______的河流，呈______状流向周边的海洋。