Water

From thebeginning,water has furnished man with a source of food and a highway to travelupon.The first civilization arose(51)________water was a dominant element inthe

environment,achallenge(52)______man's ingenuity.The Egyptians invented the 365一day calendar in response to the Nile's annual flooding. The Babylonians,(53)

________were amongthe most famous lawmakers in ancient times,invented laws(54)_________ waterusage.Water inspired the Chinese to build a 1,000-(55)

________canal,acomplex system which,after nearly 2,500 years,remains stillpractically(56)_______ and still commands the astonishment of engineers.But(57)

_________never foundcomplete solutions to their water problems.The Yellow River is also known as"China'sSorrow" ;it is so unpredictable and dangerous(58)

_________in a singleflood it has caused a million(59)________.Floods slowed thegreat(60)_________of the Indus River Valley,andinadequate drainage ruined (61)

________of its land.Today water dominates man (62)_______it always has done.Its presence continuesto(63)________the location of his homes and cities;its violent

variabilitycan(64)________man or his herds or his crops;its routes linkshim(65)________his fellows;its immense value may add to already dangerouspolitical

conflicts.There aremany examples of this in our own time.

_________(54)

A.regulates

B.regulate

C.regulated

D.regulating