Our future house will be on (a /an/the)ocean.It will be surrounded be tall trees and blue sea .But we only have salt water in ocean .We need fresh water for ( drink/drinking /to drink/to drinking)and for growing food (in/on/at/into)farms.

Ocean water is too salty (drink/drinking/to drink/to drinking).It is also too salty for watering plants .We must have the waysto make fresh water from salty water.We should be (careful/careless/carefully/carelessly)not to waste water