完形填空。

      Li Lin is a good friend of mine. I go to 1 home for dinner. Zhang Tao and Wang Dong are 2at his home. We 3 a good dinner. There is 4 chicken, fish, milk and vegetables 5 the table. And there 6 some rice, noodles, cakes, water and tea on it, too. We like 7 very much. Li Lin and I like 8 meat, fish, noodles and cakes. Zhang Tao and Wang Dong like to eat chicken, fish and 9.They are really (确实地) nice. 10 are very happy.

读图，回答：该河段洪涝灾害多发的主要原因是(   )

①上游支流多，呈扇形水系②流量季节变化大③河道弯曲，水流不畅④人们砍伐森林，围湖造田