Insomecountriesinwhichthereisverylittlerainatanytime,...
问题详情： Insomecountriesinwhichthereisverylittlerainatanytime,thefarmershavetoirrigatetheirfields.Irrigationiseasyenoughifthereisagreatrivernearthecrops,andifthereisplentyofwaterinit.Canalscarrythe...