根据下面短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
The Mississippi
The Mississippi is a great river whose relationship with man goes way back beyond its discovery in the 16th century. The River Indians used it as a highway and as a source of food, and it was they who gave it its name —— “misi” meaning “great” and “sipi” meaning “water”. When the length of its branch, the Missouri, is added to it, the Mississippi becomes greater.        . From the source of the Missouri to the tip of the delta (三角洲), it is 2, 480 miles long.
Great rivers are likely to suffer floods. In 1927 the Mississippi flooded 26 thousand acres, sweeping away farms, towns, everything in its path. In 1938 its floods drowned or killed 200 people and made millions homeless. Today the river has largely been controlled.    .
Industries have spread down some of the waterways of the delta, but otherwise the delta is a remote place, the homeland of a little colony of French Canadians that the British drove out of Nova Scotia in the 18th century. They still speak French, mixed with English, Indian, Spanish and Negro idioms. They keep to themselves, fanning the rich soil of the delta.     __.
    . Pioneers who first reached its banks wondered not only where it went, but what lay beyond. In 1764 the French founded a city on the right bank of the river, and named it after their king, Louis XV. This city, named St. Louis, became the jumping-off place for the adventurous men and women who opened up the Great Plains, and the way to the Far West.
Some 40 years earlier, at the beginning of the 18th century, the French had founded another city just above the Mississippi delta, New Orleans.   . New Orleans is one of the great ports of the world, and one of the greatest terminals for both sea and river traffic.

A．It was the Mississippi that made the city what it is

B．Levees, high banks built of earth, hold back the flood waters

C．Therefore, as we know, it’s the third longest river in the world

D．It is known that the “Great Water” has also been a frontier river

E. However, they paddled up and down the Mississippi in their boats to seek their fortune
F. The “Great Water” always remains a thread (分界线), for the streets of the city are below the level of the river
G. They call themselves Cajuns, who have actually been leading fairly primitive lives and preserving their own traditions