D
Do you know anything about rivers? 36. They affect(影响) the earth and the people in many ways.
37. Snow on a mountain turns into water and the water becomes(成为) a river. At first,a river can be very narrow(窄的). 38. A river can be as wide as a town.
39. We can see a lot of villages(村庄) along the rivers. People use the water to plant food on farms. Fish in water can also be delicious food. Boats on rivers can take things or people from here to there.
40. Many people like swimming or taking a boat on the river.
All in all,the river is making a great difference to the earth and the people.
根据材料内容,从下面五个选项中选出能填入文中空缺处的最佳选项,使文章意思通顺、内容完整。
A. Rivers are moving across the land.
B. People can also use rivers for fun.
C. A river may start high on a mountain.
D. But by going down,rivers get bigger.
E. People usually set up(建立) villages next to rivers.

36. A
37. C
38. D
39. E
40. B

36. 空格前提问是否了解河流，空格后说明河流对地球和人类有诸多影响，A选项“Rivers are moving across the land.”（河流在陆地上流动）能自然承接上下文，引出河流的基本情况，符合语境。
37. 空格后提到山上的雪融化成水形成河流，C选项“A river may start high on a mountain.”（河流可能发源于高山之上）与后文内容呼应，解释了河流的起源，符合逻辑。
38. 空格前指出起初河流很窄，空格后说明河流可以和城镇一样宽，D选项“But by going down,rivers get bigger.”（但随着向下流淌，河流变得越来越大）通过转折关系衔接前后，体现河流从窄到宽的变化，符合语境。
39. 空格后提到沿河有很多村庄，人们用水耕种等，E选项“People usually set up(建立) villages next to rivers.”（人们通常在河流附近建村庄）引出后文关于河边村庄及人类活动的内容，衔接自然。
40. 空格后提到人们喜欢在河里游泳或划船，B选项“People can also use rivers for fun.”（人们也可以用河流来消遣娱乐）概括了后文的娱乐活动，符合语境。