【单选题】

Water, water every where. 

It lasted almost two months , but in August it ended. It left 45 people dead and $10 billion worth of damage in nine states of USA. It was quite a big Mississippi flood ever recorded. 
In St.Louis, Missouri, 9,000 people were forced to leave their homes while the city was in danger. St. Louis is just downriver from the points where the Missouri and Illinois Rivers flow into the Mississippi. All three rivers were flooding. But the city escaped the worst when levees (堤) broke upriver. A levee is built of river sand and clay(粘土). 
Eleven miles of flood walls were built in the late 1960's The walls are 18 inches thick and 5 to 22 feet high. They were designed to protect against a 52-foot flood. In St. Louis, water almost reached the top of flood walls. It measured 49.4 feet. 
41.The flood referred to in the passage _____. 
A. was the heaviest one in the history B. happened in Missouri and Illinois states 
C. happened in less than twenty percent of the states of U.S.A. 
D. was recorded several times 
42. The meaning of the sentence "But the city escaped the worst" is that _____. 
A. many people escaped from the city B. the flood attacked the city heavily 
C. the flood did not attack the city at all D. the city avoided the worst situation 
43. The highest flood referred to in the passage was about ______. 
A. 18 feet high B. 5-22 feet high C. nearly 50 feet high D. 52 feet high