英译汉The flood waters carry in them soil (called silt) from th

英译汉
The flood waters carry in them soil (called silt) from the upper parts of the river valley to the lower parts,and so to the sea.But as the river meets the sea,the sea acts as a barrier and forces the river to drop the silt it is carrying.
There are no tides in the Mediterranean to carry the silt away,so year after year it collects at the mouth of the Nile,and the river must find its way around islands of silt to the always more distant Mediterranean.In this way,a vast area of fertile soil has been built up at the mouth of the Nile and out into the sea.The river water splits up to form small branches winding across the area.To the ancient Greeks,the mouth of the Nile looked like the drawing.
Now we sometimes name things after the letters of the alphabet they resemble:a U-turn,an I-beam,a T-square,an S-bend,and so on.The Greeks did the same.The triangular area of land built up at the mouth of the Nile looked like the fourth letter of the Greek alphabet delta ( Δ ) and so this was the name they gave it.The word is now used for all areas of land formed at the mouth of rivers which flow into tideless seas,even when they are not triangular in shape.The Mississippi delta,for example,is not shaped at all like the Greek delta,as you will see if you look at a map.

洪流夹带着泥沙从上游河谷流向地势低洼的地区,也是通过这种方式流入海洋.但是当河流汇入大海的时候,大海起到了屏障的阻挡作用,使得河流中携带的泥沙沉降下来.
在地中海,没有潮汐洋流将淤泥运走,所以年复一年,尼罗河的河口逐渐闭塞,所以河流必须要绕开淤泥形成的三角洲岛屿流向遥远的地中海.通过这种方式,在尼罗河河口形成了广袤的肥沃土壤.河水分成小股河流穿越这片区域.在古希腊人看来,尼罗河入海口像一幅画卷.
我们现在命名事物的时候,总喜欢用相似的字母来描述：比如U形转弯,I形梁,S形曲线等等.希腊人也这么做.这片尼罗河口的三角洲看起来像希腊字母的第四个字母代尔塔( Δ ),所以他们以这个字母命名这片三角洲.现在这个字母被用于命名所有因汇入无潮汐海洋河流所形成的三角洲,就算形状并不是三角形.比如你在地图上看看密西西比代尔塔,它的形状并不像希腊字母代尔塔（Δ）.