Irrıgation is the practice of artificially suppliying water to land to sustain the growth of crops .An ancient agricultural technique,irrigation may have been practised as early as 5000 BC along the banks of such regularly flooding rivers as the Nile ,by digging channels to extend the area covered by the flood ,and by erecting dikes to trap water on the land after the river had subsided.The development of diversion dams and of water –lifting machines permitted the irrigation of lands lying above those normally reached by floodwaters.Modern irrigation systems are still based on these two key engineering innovations.

Today people,…………
a-have devised many differnt ways to supply water to land
b-still rely on flooding rivers for irrigation
c-basically use the same irrigaiton techniques as ancient ones
d-have developed more efficient irrigation systems than their ancestors
e-are no longer helpless aganist floodwaters

c galiba değilse b olmalı.

Irrıgation is the practice of artificially suppliying water to land to sustain the growth of crops .An ancient agricultural technique,irrigation may have been practised as early as 5000 BC along the banks of such regularly flooding rivers as the Nile ,by digging channels to extend the area covered by the flood ,and by erecting dikes to trap water on the land after the river had subsided.The development of diversion dams and of water –lifting machines permitted the irrigation of lands lying above those normally reached by floodwaters.Modern irrigation systems are still based on these two key engineering innovations.

Today people,…………
a-have devised many differnt ways to supply water to land (not stated)
b-still rely on flooding rivers for irrigation
c-basically use the same irrigaiton techniques as ancient ones
d-have developed more efficient irrigation systems than their ancestors (not stated)
e-are no longer helpless aganist floodwaters (not stated)

C şıkkı derdim...

Irrıgation is the practice of artificially suppliying water to land to sustain the growth of crops .An ancient agricultural technique,irrigation may have been practised as early as 5000 BC along the banks of such regularly flooding rivers as the Nile ,by digging channels to extend the area covered by the flood ,and by erecting dikes to trap water on the land after the river had subsided.The development of diversion dams and of water –lifting machines permitted the irrigation of lands lying above those normally reached by floodwaters[/B].[B]Modern irrigation systems are still based on these two key engineering innovations.

C şıkkı derdim...
bende burdan d şıkkı dedim.:) doğru cevap c

Sen bana D nin içinde olduğu bir cümle göster tamam diyeyim. Bu cümleler çelişkili;

-Modern irrigation systems are still based on these two key engineering innovations.

-have developed more efficient irrigation systems than their ancestors

Ayrıca daha etkili bir sistemden bahsedilmiyor...:)